They are mandatory on most cars and are one of the main safety features of modern driving. But what exactly does TPMS do?

With all the talk about new car features like multi-zone climate control systems, heated steering wheels, smart suspension, or evasive steering, it’s easy to forget how vital something as simple as a tire is to your car’s performance. As the only connection point between the road and the vehicle, having the right tires and ensuring they are in perfect condition is more important than the extravagant extras you might have.

Keeping your tires in order and ensuring you can drive safely and efficiently is precisely what tire pressure monitoring sensors are for. These sensors have been deemed so important that they are a mandatory feature on all new passenger cars from 2008 in the United States and from 2014 in the EU, and there is a wide variety of aftermarket systems you can install on older vehicles. Although extremely useful, what these systems do may not be immediately obvious, and if they go wrong, they can often mean an expensive trip to the dealership. This is a comprehensive guide on what tire pressure monitoring systems are, how they work, and what the benefits of having them are.

What are Tire Pressure Monitoring Systems (TPMS)

Tire pressure monitoring systems (or TPMS) are designed to primarily monitor the air pressure in a car’s tires. The system consists of sensors connected to each wheel and a display unit. If the system is integrated, the sensors will be connected to a light on your dashboard, normally a yellow symbol that is the cross-section of a tire with an exclamation point in the middle. If the system was installed after production, it will often come with a display unit that can sit on your dashboard and is connected to the sensors. In addition to pressure, it can also transmit information about the tire’s temperature, as well as give you important updates on the condition of the tires.

How do Tire Pressure Monitoring Systems Work

The basic principle of TPMS is that information about a vehicle’s tire pressure is collected (there are different ways to do this), then sent to the control unit on your dashboard. The system is programmed to monitor tire pressure levels and ensure they remain at an acceptable and safe pressure, often between 28 and 35 pounds per square inch (psi) of air in the tire for most passenger cars. If something is wrong, the light or alarm will let you know.

Some systems will allow you to access your tires’ temperature and pressure value at any time, allowing you to manage your tires. There are two main types of TPMS, direct and indirect, and they both collect this tire pressure data in different ways.

Direct Tire Pressure Monitoring

In direct tire pressure monitoring systems, individual sensors are located directly on the tires (and sometimes in a spare tire) and they transmit information to a central control module. These systems consist of a sensor mounted on the vehicle that communicates with the central control module. This information is most often gathered using a microelectrochemical system. At the control module level, it is analyzed, interpreted, and if the tire pressure is lower than it should be, or if the tires have been severely over-inflated, transmitted directly to your dashboard where the light comes on.

The information is most often sent wirelessly as a radio signal. Each sensor has a unique serial number, and the system can distinguish with these not only between different vehicles on the road but also between the different tires of the car. While some aftermarket systems are mounted on the outside of the tire, most manufacturers use a sensor mounted inside the tire. The battery life of one of these integrated sensors is about a decade, but for most systems, the battery is not repairable and the entire sensor must be changed.

Direct systems can be mounted in different ways. They can either be mounted on the back of a tire’s valve stem or secured using an adhesive or to a strap that is then tightly wrapped around the inner rim of the tire.

Indirect Tire Pressure Monitoring

Indirect tire pressure monitoring systems do not rely on tire pressure sensors to operate and make assessments about the tire. These systems gather and take into account data from wheel speed sensors (easily available through ABS or similar systems) to interpret a tire’s size and its rotation speed – a smaller tire would spin faster than a larger tire and an under-inflated tire would be smaller than one with the right amount of air. The system detects if a tire is moving faster than the others and can calculate that it is smaller and therefore possibly deflated. If this happens, it emits a warning light just like direct tire pressure monitoring systems.

One of the great advantages of this system is that it seems less fragile than direct sensors, but it needs to be reset more often. For example, if the tires are inflated before a long trip, an indirect system should be reset, as it would see the newly inflated tires as a possible danger. The system should always be at rest when the tires are inflated. In this case, if it is not reset, the system will see larger tires and may warn the driver of over-inflation. The TPMS must be recalibrated not only when the tires are restored to the correct pressure but also when the tires are swapped or completely replaced. This can often be performed from the car’s cabin via a recalibration button on the center console and takes about 30 minutes of driving to reset.

What are the Benefits of Tire Pressure Monitoring Systems

1. Long-lasting Tires – Regularly checking your tire pressure and inflating them if necessary, with the help of TPMS, can significantly increase the longevity of your tires. If the tire pressure is incorrect, whether too low or too high, a tire’s lifespan can decrease by up to 45%. If the pressure is too low, the tire will overheat and the edges of the tire will wear out. If the pressure is too high, the center of the tire will bulge and wear out. All this means that you will be replacing tires much sooner than necessary to buy new ones.
2. Improved Handling – As stated at the beginning, tires are extremely important and are the link between the road and the car. Your car’s handling depends almost entirely on your tire pressure. If the wrong amount of rubber is on the road, it can reduce traction and handling in corners. This can happen if the tire is over-inflated. If a tire is deflated, it also increases the risk of hydroplaning in rainy weather due to a lack of traction between the flat tires and the road surface.
3. Improved Fuel Economy – The TPMS system can also impact a car’s fuel consumption. With the right amount of air in the tire, a car has less rolling resistance and therefore doesn’t need as much to roll on normal roads. But if there is less air in the tire, the tire’s surface is less firm and thus there is more rolling resistance because the tire drags more on the road. As there is more resistance, the car needs more energy to travel the same distance, and of course, it will take more fuel to go from A to B.
4. Easier to Spot Problems – In addition to helping solve these more general problems, TPMS can also help you see a serious issue developing. If the system lets you know that a tire has much less pressure than the others, you might have a puncture or a slow leak, which, just by feel, can be very difficult to detect. If a tire is about to delaminate, separate, or blow out, all potentially serious issues, by indicating that the tire has low pressure, TPMS will let you know in advance. This makes it an essential safety feature for any vehicle.

Are there any Downsides to Tire Pressure Monitoring Systems

1. Fragility – The vast majority of direct TPMS monitors are part of an assembly that includes the valve stem. When the valve stem is installed, the sensor is located inside the tire. The major problem with this is that the sensor and the attached stem are relatively fragile. Due to how the sensors are placed next to the wheel, removing the tire can be a very delicate process, as if the tire’s bead presses against the sensor, it could break it. They are known to be susceptible to damage, and as a result, most tire shops will not accept any responsibility for damage to the stems or sensors. Although they have become more robust, most OEM sensors are still dealer-only items that can cost between 60 and 120 euros each. Some aftermarket options are now available, but replacing a sensor remains an expensive undertaking.
2. Lack of Standardization – Almost all car manufacturers have their own exclusive TPMS system, and since there is no standardization, most parts are dealer-only. Unless you are using an aftermarket system, which is unlikely on cars produced after 2014, it can be difficult to replace a faulty system. This also makes it harder for auto shops and garages to correct defects, as even they can find the systems used by each manufacturer confusing. In turn, this means that repairs or replacements are often best done at a dealership directly by the manufacturer, which will almost certainly be costly.
3. The Need to Reset Sensors – TPMS computers often need to be reset after moving a wheel on the car, or if a sensor needs to be replaced, and the process of finding how to reset your car’s system can be exasperating. In the best case, your car may only need to be driven a certain distance or for a certain time (as is usually the case with indirect TPMS). In the worst case, there may be a complex way to reset the system using your car’s control buttons, which can be frustrating. They are sometimes so complicated that there are books and software with instructions on how to reprogram most systems, but even these can be incomplete, confusing, or directly conflicting with the instructions in the car’s manual.
4. Inaccurate Readings – This can happen for various reasons, such as fitting larger or smaller tires and uneven wear with indirect TPMS. Direct TPMS should be better, but depending on where the sensor is installed and if it is poorly placed (they are very fragile), it could also provide readings that do not reflect the actual tire pressure.

Tire Pressure Monitoring Systems: The Last Word

So, TPMS is a complex system, but the benefits it can offer to motorists far outweigh the potential problems. Even if it seems expensive to replace some parts, correct tire pressure should save you much more in terms of fuel and in terms of safety as well. Many of these issues mentioned above could be resolved – and are being resolved – by improved indirect TPMS systems that use sensors in the ABS hardware to perform their magic. These types of systems are becoming more common and could make the entire TPMS repair process much easier.

Causes of a Car Starting Then Immediately Stopping. What’s more frustrating than a car that starts for a few seconds and then completely shuts off, and this happens every time you try?

Not much, if you ask me! You should know that this is a fairly common problem, so you are certainly not alone, and there are easy solutions to this issue.

In this article, we will go over the 10 most common reasons why your car starts and then dies immediately.

Here is a more detailed list of the most common reasons why your car starts and then dies:

Lack of Fuel

The most common reason why your car starts and then dies is due to a lack of fuel in the engine. This often happens because there is a small amount of fuel in the fuel rail, which helps the engine start, but there is no fuel pressure to keep the engine running.

Lack of fuel is, however, quite easy to diagnose. You can either connect a fuel pressure gauge to the fuel rail or carefully loosen a bolt while starting the engine to see if you have fuel pressure. Be careful so you don’t set anything on fire.

If you realize that your car has low fuel pressure,

Anti-Theft Alarm System

The second most common thing is any issue with the anti-theft or anti-theft alarm system. When the anti-theft system is activated, the car does not send any power to the fuel pump, which creates fuel pressure in the fuel rail. This will cause the car to start for a few seconds, as we have already discussed.

If the anti-theft alarm system is factory-installed, you should have a key symbol on your dashboard that should turn off a few seconds after turning the ignition on. If it doesn’t, try locking and unlocking your car and try again. If it is still on, there may be a problem with your car key.

If you have an aftermarket anti-theft alarm, there may be a problem with the alarm itself or a faulty remote.

Dirty Fuel Filter

If the car stops after turning the ignition on, the problem could be a lack of fuel, as we have already discussed. A fuel filter is a common thing that causes low fuel pressure.

The fuel filter is a filter that you need to replace on a schedule, which depends on your car model. If you haven’t replaced it for a long time, it may be clogged.

Fuel filters are often quite easy to replace and inexpensive. If you have low fuel pressure, it may be worth trying to replace it.

Bad Idle Control Valve

The function of the idle control valve is to maintain your car’s idle. Newer cars control the idle with the throttle body, but if you have an older car with a throttle cable, you have an idle control valve.

Often, this idle control valve can get dirty, which will prevent the idle from functioning properly. You can try cleaning this valve to see if it improves. Otherwise, you need to replace it or repair the wiring.

Vacuum Leak

The throttle body or idle control valve controls the idle by regulating the amount of air entering the intake manifold. If you have a major vacuum leak, it can actually make the car’s air-fuel mixture too lean and cause it to die after a few seconds every time you try to start your car.

Vacuum leaks are often quite easy to locate, either by using an EVAP smoke machine or simply by listening for the leak, as it will often cause a high-pitched sound.

Faulty Spark Plugs

The combustion engine works by igniting an air-fuel mixture. The spark plugs provide the spark for this ignition. The pistons move up and down, which causes movements in the crankshaft and wheel axles.

If the spark plugs are faulty, the ignition will fail and the car will stop moving. This can cause the car to start for a second but misfire too much with a weak spark, so the engine will die very soon.

Fuel Injector

Fuel is injected under high pressure into the combustion chamber using the fuel injectors. The job of the fuel injectors is to regulate so that the exact amount of fuel needed enters the combustion chamber.

If a fuel injector fails, it can cause the engine to run on fewer cylinders and also cause a drop in fuel pressure if one of them is stuck open.

You can try to feel the fuel injectors with your hand during startup to see if they click. If they don’t make any clicking sound, one of them may be faulty.

Faulty Ignition Switch

If your ignition switch is damaged, you can start the car normally, and after a few seconds, the car will stop completely. If your ignition switch is faulty, you need to check the wear on the switch contacts.

The ignition switch is located behind the car’s ignition lock. In newer cars, it is most often not possible to replace the ignition switch itself; you have to replace the entire ignition lock.

Faulty EGR Valve

The EGR valve controls the exhaust gases that need to be recirculated into the engine. If the EGR valve is stuck open, it can allow too much air into the intake manifold.

This can make the mixture too lean, which will also cause the car to start and then die after a few seconds.

Engine Control Unit (ECU)

The ECU is a computer system that controls various engine functions, including the fuel injection system. Since a vehicle needs fuel to move, any malfunction of the ECU will cause the vehicle to stop after starting.

The ECU controls engine components via a series of sensors. Over time, sensors become faulty and transmit incorrect information to the ECU. In this case, you need to take your car to an auto repair shop.

Knowing the temperature is very useful. If you go outside, you look and see that it’s 28 degrees and you should wear a warm hat. Although your car doesn’t wear cozy hats, it’s essential that it constantly monitors the engine temperature when it’s running.

That’s the job of the engine coolant temperature sensor (CTS or ECTS). Coolant is also called antifreeze, the liquid that helps keep the engine at an optimal operating temperature.

The vehicle can do several things to change the temperature if needed, so the temperature data that the CTS sends to the ECU (the car’s main computer) is essential.

Some vehicles also have a cylinder head sensor (CHS) located at the top of the cylinder and is not affected by coolant loss because it is not submerged in coolant like the CTS. This makes the CHS more reliable than the CTS.

How Does a Coolant Temperature Sensor Work?

The CTS uses electrical resistance to measure temperature, meaning the CTS is a thermistor. The sensor’s resistance (opposition to electrical flow) changes proportionally with temperature – as the temperature increases, the electrical flow also increases.

The ECU sends the electrical signal through the CTS, measuring the voltage drop. This converts the electrical flow information into a temperature reading.

With this information, the ECU adjusts fuel injection, ignition timing, and the electric radiator cooling fans to maintain an optimal temperature. If the engine is cold, the ECU directs the air/fuel mixture to be richer, or a higher proportion of fuel for the amount of air entering the engine.

If the engine starts to get too hot, the ECU will kick on the radiator fans. This is normal behavior when you’re sitting at a long stoplight on a hot day, for example. Some cars shut off the engine in case of overheating to protect itself from engine damage.

The temperature information is also sent to the dashboard gauge, which is usually located next to the fuel gauge.

Symptoms

of a Bad Coolant Temperature Sensor

All parts eventually wear out, and this sensor is no exception. It is essential to address cooling system issues because if the vehicle ends up overheating, it could cost you an engine (which is very expensive and time-consuming to repair).

1) Overheating Engine

An overheating engine should give several warnings like a high temperature reading on the dashboard gauge and sometimes white “steam” coming out from under the hood (that’s boiling coolant, meaning it’s leaving the system – that’s bad!).

Not having enough coolant is one problem. A coolant leak can also cause the engine to overheat if there isn’t enough reserve to cool the engine properly.

2) Poor Engine Performance

If the sensor is faulty, it can send incorrect temperature information to the ECU, which can lead to strange engine behavior, like general “weakness” or sluggishness.

If the vehicle is lagging during acceleration, accelerates slowly, idles roughly, or is hard to start, especially when it’s already warmed up, it’s worth checking the CTS.

3) Increased Fuel Consumption

You might see your fuel economy deteriorate significantly if the sensor is faulty, as the computer may direct too much fuel to be injected into the cylinders.

4) Black Smoke from Exhaust

For the same reason, the vehicle can run too rich, causing the excess fuel to burn in the exhaust and making other drivers look at you.

5) Failed DEQ Emissions Test

If too much fuel or an abnormal amount of byproducts are expelled due to inefficient combustion, it will show up during an emissions test as something that needs to be fixed.

The CTS could be the culprit, although there are several sensors and seals that need to be checked.

6) Inaccurate Temperature Gauge

If the engine temperature reading on the dashboard gauge seems incorrect (for example, if the gauge reads “cold” when the car is fully warmed up), the coolant temperature sensor might be receiving faulty information.

7) Check Engine Light is On

The dashboard “check engine” light comes on when the ECU detects a problem and logs a code. If you see this along with any of the other symptoms, it’s worth checking the CTS.

8) Cabin Air Conditioner Stops Working

Many vehicles put the car into a “fail-safe” mode if overheating is detected. This can stop the engine, run the engine cooling fans continuously, and disable the interior air conditioning to allow the car to dissipate engine heat more effectively.

You can ignore many small problems when it comes to cars, but you should never ignore problems with the brakes.

If you notice that your brake pedal goes to the floor when the engine is running, you need to be very careful about this. This can lead to the complete disappearance of the braking function!

Therefore, it is certainly not recommended to continue driving your car if you experience something like this. But what causes it and how can you fix it? Let’s find out!

Causes of Brake Pedal Going to the Floor When Engine is Running or Starts

1. Brake Fluid Leak
2. Faulty Brake Master Cylinder
3. Faulty Brake Booster
4. Air in the Brake System
5. Low Brake Fluid Level

These causes are the most common reasons why this problem can occur. Here is a more detailed list of the common causes of the brake pedal going to the floor when the engine is running or when starting the car.

Brake Fluid Leak

The most common reason this happens is that you have a brake fluid leak somewhere in the brake system. This is often due to a rusty brake line, but it can also be seal leak issues at the caliper pistons.

Brake fluid leaks are often very visible on the floor; however, if you have seen a puddle of fluid on the garage floor, it is definitely time to look for brake fluid leaks.

When you press the brake pedal with a fluid leak, the brake fluid flows out. When the brake pedal comes back up, it will suck in air through the leak instead, which will make your brake pedal very spongy.

Faulty Brake Master Cylinder

Another common reason your brake pedal goes to the floor when the engine is running is caused by a faulty brake master cylinder. The brake master cylinder is located behind the brake pedal on the other side of the engine compartment firewall.

The purpose of the brake master cylinder is to push brake fluid to the caliper pistons to reduce the vehicle’s speed.

The brake master cylinder has a seal around the push piston, and if this seal starts to leak, the brake pressure will return from the other side of the piston when you press the brake pedal.

This will cause a constant loss of pressure from your brake pedal when you press it, which will feel like a spongy or sinking brake pedal.

Faulty Brake Booster

Between the brake master cylinder and the brake pedal, you will find the brake booster. The brake booster uses a vacuum to increase braking power when you touch the brake pedal.

If you have ever driven a car without a functional brake booster, you know how much pressure it requires without it.

If your brake pedal starts to build pressure very low, but feels very stiff once it gets near the bottom, you likely have a problem with your brake booster. It is not very common for the brake booster to fail, but it does happen on some car models.

Air in the Brake System

Have you or someone else recently replaced something in the car’s hydraulic brake system without performing a proper brake bleed afterwards? Then that might be your problem!

Air is compressible, unlike brake fluid. Therefore, the brake system must be completely free of air for quick pressure build-up, and not to get a spongy brake pedal.

The only way to remove air from the brake fluid system is to bleed it properly.

Low Brake Fluid Level

If you have a brake fluid level warning light on your dashboard, it is definitely time to check the brake fluid level.

If the brake fluid level is low, air can enter the brake system when you take sharp turns, for example. What happens with your brake system when you have air inside, we discussed in the previous section.

If your brake fluid was so low that air enters the system, simply refilling it would not be enough. You need to bleed the brake system again.

How Do You Fix a Brake Pedal That Goes to the Floor When the Engine is Running?

Now that you know the common reasons why your brake pedal might sink to the floor, you probably want to know how to diagnose and how to fix this problem. So let’s get started.

1. Look for External Leaks: Check everywhere under your car for any sign of brake fluid leakage. Check the brake lines, hoses, and brake calipers. The most common leak comes from rusty brake lines, but can come from bad rubber seals in the caliper pistons. Replace the leaking part.
2. Check Brake Fluid Level: Check the brake fluid level in the engine compartment reservoir and fill it to MAX if necessary. If the fluid level was really low, there is a risk of air in the brake system, meaning you need to bleed it.
3. Bleed the Brake System: The next step is to bleed the brake system to remove all the air from it. You can find it in this video to discover the complete process of bleeding the brake system at home.
4. Disconnect the Brake Booster Vacuum Hose: Disconnect the vacuum hose from the brake booster and try pressing the brake pedal again. If the problem persists, you likely have a faulty brake master cylinder.
5. Check or Replace the Brake Master Cylinder: Remove and inspect the brake master cylinder for any signs of seal damage. For most brake master cylinders, you cannot buy the seal alone – so you need to replace the brake cylinder.
6. Inspect or Replace the Brake Booster: The final step is to inspect and replace the brake booster if you see anything suspicious with it. However, if everything else seems fine and you are 100% sure there is no more air in the brake system, there is a high chance the brake booster is the faulty part.

FAQ About Brake Pedals

Car engines operate by combusting an air/fuel mixture. Spark plugs are used to provide the necessary spark for ignition. This will then move the pistons and crankshaft.

However, inefficiencies can lead to more fuel being supplied to the engine than necessary. When this happens, we say the engine is running rich.

Having a rich fuel car means you are spending a lot on fuel. Therefore, it is necessary to repair your rich running engine as soon as possible.

Causes of Engine Running Rich

1. Faulty MAF Sensor
2. Faulty O2 Sensor
3. Faulty MAP Sensor
4. Faulty Engine Coolant Temperature Sensor
5. Faulty Intake Temperature Sensor
6. Faulty Fuel Pressure Regulator
7. Faulty Fuel Injector

This can explain many reasons why an engine runs rich, as there are so many parts in an engine that can affect the fuel mixture.

Here is a more detailed list of the most common causes when your engine is running well.

Faulty MAF Sensor

A faulty MAF sensor is the most common cause of an engine running rich.

The MAF sensor calculates the air entering the engine, then calculates the air-fuel mixture to add. If it is dirty or malfunctioning, it will cause the engine to run too rich or too lean.

If the MAF sensor is faulty, it will calculate the wrong amount of air entering the engine and add too much or not enough fuel.

Faulty O2 Sensor

O2 sensors are located on the exhaust pipe to detect the air-fuel mixture from the previous combustion.

If the O2 sensor gets information suggesting a lean mixture, it will tell the engine control unit to add more fuel during the next combustion and vice versa.

If it is faulty and tells the engine control module to add more fuel, even if the air-fuel ratio is good, it can cause a rich fuel mixture. A faulty O2 sensor can make the engine run too rich.

Faulty MAP Sensor

In some cars, they have a MAP sensor instead of the MAF sensor. There are also cases where you can have both a MAP and MAF sensor.

The MAP sensor calculates the air-fuel mixture based on the air pressure in the intake manifold. If you have a MAP sensor, it is absolutely worth checking this part.

Diagnosing the MAP sensor is quite easy with a diagnostic tool as you can check the pressure it displays when the engine is off, which should be the same pressure as our air pressure.

Faulty Engine Coolant Temperature Sensor

When the engine is cold, the engine needs more fuel to operate properly. It is the job of the engine coolant temperature sensor to measure the coolant temperature to identify when it needs to add extra fuel to the engine.

If the engine coolant temperature sensor is faulty, you can get a mixture that is too rich.

Faulty Intake Temperature Sensor

The intake temperature sensor calculates any additional fuel that needs to be added or restricted based on the temperature of the air entering the engine.

The intake temperature sensor is often installed inside the MAF sensor and cannot be replaced separately.

Faulty Fuel Pressure Regulator

A faulty fuel pressure regulator will result in fuel pressure that is too high or too low. This can cause a mixture that is too rich.

You will also want to check the fuel pressure regulator’s vacuum hose to ensure there are no leaks around it.

Faulty Injector

Injectors are the ones that manage the amount of fuel entering the engine. If an injector is not flowing as it should or is stuck open, it can cause a rich mixture in your engine.

7 Symptoms of an Engine Running Rich

1. Check Engine Light
2. Fuel Smell from Exhaust
3. Constantly Refilling Your Gas Tank
4. Poor Engine Performance
5. Black Smoke from Exhaust
6. Sooty Spark Plugs
7. High Carbon Monoxide Content

If you think your engine is running with a rich mixture, you need to check a few things to confirm it.

Here is a more detailed list of the most common causes when your engine is running well.

Check Engine Light

When the fuel/air ratio is high, the check engine light comes on.

The engine control module monitors all sensors, and if a sensor in your car is not working properly, it will turn on the check engine light on your dashboard.

Fuel Smell from Exhaust

If excess fuel is heading to the combustion chambers, it means some of it will not be completely ignited.

The catalytic converter has a way to remove some of this fuel, but it will find its way into the exhaust system when in excess. Unburned fuel smells like rotten eggs.

Constantly Refilling Your Gas Tank

One of the symptoms of a running engine is that you are not getting the proper fuel consumption. This is because the car does not need all the fuel supplied. However, it is normal to spend more on gas in winter or when carrying heavy loads.

Poor Engine Performance

For your car’s engine performance to be normal, there must be the right amount of fuel/air mixture. The assumption is that if there is an overflow of fuel, the car will move faster. This is not the case because the excess fuel does not burn.

When you experience issues with the air/fuel ratio, the car’s performance is poor. Additionally, you will notice that whenever your car is idling, the RPMs keep moving erratically.

Black Smoke from Exhaust

When your engine is rich, it will cause poor emissions. A rich air-fuel mixture will create black smoke, which will then come out of your exhaust pipe.

If your exhaust pipe makes you feel like you have a diesel engine, but you don’t, it’s really time to check the air-fuel mixture.

High Carbon Monoxide Content

Carbon monoxide is a dangerous exhaust gas. The catalytic converter works overtime to remove any trace of carbon monoxide in the exhaust. When your car’s engine is rich, it means you are producing more gasoline.

This can be dangerous when you are in a closed, poorly ventilated room. You also risk failing state-sanctioned emissions tests.

Sooty Spark Plugs

If your engine is running rich, the spark plugs accumulate black deposits at the bottom. This prevents them from working efficiently. The soot will find its way to other engine parts, causing further damage.

The unburned fuel eventually ends up in the catalytic converter, and due to the number of impurities, it will clog it. Over time, you will be forced to dismantle and replace it.

Engine Running Rich Diagnosis

Diagnosing a rich engine is really not that simple. It often requires diagnostic skills if you want to waste money on simply replacing parts.

This is how a professional would do it, and you might need additional tools to do so.

1. Connect an OBD2 scanner and check the associated fault codes. If you find another fault code regarding another sensor, start your diagnosis at the sensor level.
2. Check the live data values of the O2 sensor. Is it showing that it is constantly decreasing the amount of fuel? Then it’s probably not a fault with that sensor.
3. If you have access to an emissions control tester or an external air-fuel meter, connect it and check the actual air-fuel meter. If it shows that the fuel mixture is lean, while the O2 sensor tells us the engine is rich and removing fuel – there is a problem with your O2 sensor and it needs to be replaced.
4. Check the values of all temperature sensors like coolant and air temperature.
5. Check the values of the MAF sensor or MAP sensor if you have one. Replace if faulty.
6. Check the fuel pressure and ensure the pressure is not too high at idle or acceleration. Check the fuel pressure regulator or vacuum hose if it is too high.

What is a Camshaft Position Sensor?

A camshaft position sensor is a component of a vehicle’s engine management system. As its name suggests, the sensor’s function is to monitor the rotational position of the camshaft relative to the crankshaft. This allows the onboard computer to know which of the cylinders is in its power stroke in the combustion sequence.

For efficient combustion to occur, the right amount of air/fuel mixture must be ignited at the right time. The camshaft is responsible for opening and closing the engine’s intake and exhaust valves. The speed at which the valves open and close depends on the engine load and speed. The valves need to be open longer at high speeds than at low speeds.

The computer combines the input from the cam position sensor and other sensors to determine the proper timings. The timings vary depending on engine load and speed, so the onboard computer adjusts the engine timings from time to time. Igniting the air/fuel mixture at precise moments in the combustion cycle ensures the engine runs smoothly and efficiently.

Symptoms of Bad Camshaft Sensors

Symptoms of Bad Camshaft Sensors

The camshaft sensor is part of the engine’s timing system. If the sensor is faulty, it will affect how the engine runs and behaves. Faulty sensors will cause misfiring, backfiring, or loss of power. Faulty cam sensors will also trigger the Check Engine light and the computer will put the vehicle into fail-safe mode.

Check Engine Light

The cam position sensor is one of the sensors that triggers the Check Engine warning if it fails. The camshaft position sensor works in conjunction with other sensors in the engine. If one or more of the sensors are faulty (like the cam sensor), it will send a warning in the Check Engine light.

Misfires

Engine misfire is a sign associated with bad cam sensors. If the sensor is worn out, it may not provide the computer with the correct camshaft position. This causes the computer to determine the timings based on a faulty sensor input. The computer will then send non-optimized timing signals to the injectors and ignition coils, causing engine misfires.

Backfires

Engine backfire is another sign of worn cam sensors. Like misfires, incorrect timings cause engine backfire. If the timing is off, the air/fuel mixture will leave the combustion chamber unburned. This unburned mixture can ignite in the exhaust system due to the heat from the exhaust manifold and exhaust pipes.

Stalling, Stumbling, or Hard Starting

The engine stalling or stumbling is another sign that the camshaft sensor is faulty. Faulty sensor inputs will cause the computer to unnecessarily retard or advance the timings. Bad sensors will also cause the valves to open too early or too late. This deprives the engine of the right amount of air needed for efficient combustion, resulting in engine power loss.

Shifting Problems

Modern vehicles are equipped with a fail-safe safety feature called “limp mode.” The car computer activates the feature if it detects a fault (such as a bad camshaft sensor) in the engine. When the vehicle is in limp mode, you will not be able to shift beyond second gear and accelerate your vehicle.

What Causes Camshaft Sensors to Fail?

Camshaft position sensors can fail due to normal wear and tear or mechanical damage. The sensors are prone to damage from contamination, vibration, and heat in the engine compartment.

Contamination and Corrosion

The cam position sensor is usually installed on the engine cylinder head. Broken gaskets and seals can cause oil and coolant to leak into the sensor. As with any electronic device, oil, water, and rust can short the sensor’s circuits.

Vibration

The engine produces a lot of vibration during operation. The sensors are designed to withstand these oscillations. However, too much engine vibration can increase sensor wear and tear. This is further aggravated by additional vibrations generated when the engine shakes violently due to incorrect timings and improper air/fuel mixtures.

Excessive Heat

Excessive heat is another cause of camshaft sensor failure. Heat in the engine compartment can cause the metal parts of the sensor to expand. This expansion will affect the sensor’s ability to send the correct input to the computer.

Can You Replace the Sensor Yourself?

Replacing the sensor is easy and you can do it yourself. You can save about $100 on labor costs alone by going this route.

Make sure the sensor is compatible with your engine when purchasing a replacement. Buying an identical sensor also reduces the risk of having compatibility issues. Replacing the sensor takes about 30 minutes. This includes removal, installation, and testing.

How to Replace a Faulty Cam Position Sensor?

If you decide to change the sensor yourself, follow these simple steps:

• Park your vehicle on a flat and level surface.
• Turn off the engine.
• Remove the negative (black) cable from the battery terminal on the battery.
• Locate the camshaft position sensor around the engine cylinder head. If you have trouble, consult your manual.
• Disconnect the sensor connector.
• Remove the sensor from the cylinder head. Sensors are usually secured by bolts.
• Install the new cam position sensor.
• Reinstall the sensor connector.
• Reconnect the black battery cable to its corresponding terminal.
• Start the engine and check if the Check Engine light is on.
• If there is no Check Engine light warning, take your vehicle for a road test.
• If the engine runs well, congratulations, the replacement is successful!

Is it Safe to Drive with a Bad Cam Position Sensor?

The short answer is no. Driving with a bad camshaft sensor poses a huge safety risk and could further damage your engine. Losing engine power while driving on the highway is dangerous, especially due to the amount and speed of traffic. You risk being rear-ended by another vehicle when you suddenly lose power.

You can still drive the vehicle, albeit in limp mode, as mentioned above. Do not attempt to drive the car longer than necessary. Faulty camshaft sensors can cause serious engine damage if ignored. Engine systems are designed to work interdependently. If the cam position sensor is faulty, it will negatively affect the ignition and fuel delivery systems.

If your vehicle shows any of the signs and symptoms of worn cam sensors, take your car for repair immediately or replace the sensor yourself.

How to Test a Bad Camshaft Sensor?

If you suspect the camshaft sensor is faulty, check the computer for trouble codes using an OBD2 scan tool. If the cam sensor is faulty, the scanner will generate codes indicating the problem.

If you don’t have an OBD2 scanner, check the sensor for damage before testing its circuits. Check the sensor for loose connections, contamination, debris, cracks, and other deformities. If there is no visible damage to the sensor, there may be a problem with the sensor circuit.

Testing bad camshaft sensors is simple and you only need a multimeter. Most modern vehicles use either the magnetic type camshaft sensor or the Hall effect camshaft sensor. The sensors are tested in situ with the ignition on, and again while the engine is running.

To test the Hall effect sensor, put the black multimeter probe in contact with the ground wire. Then connect the red probe to the sensor’s signal wire. The voltage across the device should comply with the voltages specified by the manufacturer. If the voltage reading is lower than specified or if there is no signal, the sensor is faulty.

To test magnetic sensors, first put the black probe of the multimeter in contact with any ground point (i.e., engine block, valve cover, engine bolts, etc.). Then connect the red probe to one of the sensor’s signal wires. If the voltage reading does not fall within the specified voltages, the sensor is faulty.

Conclusion

A functioning camshaft position sensor keeps your engine running smoothly and efficiently. Replace damaged sensors immediately to avoid damaging your engine. Since replacing the sensor is easy, the best option is to replace it yourself to save money.

If you have ever driven a car and noticed a loss of power while accelerating or even during normal driving, you know how frustrating and even dangerous it can be. Several factors can explain this problem, often related to a lack of maintenance, wear and tear, or mechanical or electronic failures. A loss of power usually results from an imbalance in the supply of air, fuel, or compression, essential elements for the proper functioning of the engine.

Identifying the exact cause may require time and effort, but to guide you, here are the 11 most common causes of power loss during acceleration. These issues can be classified into three main categories:

1. Sensor Malfunctions
2. Actuator Problems
3. Mechanical Failures

Each category includes critical components that can affect your engine, whether you drive a gasoline or diesel vehicle. Discover below the details for each possible cause and their solutions.

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1. Sensor Malfunctions

Sensors are crucial in modern vehicles with advanced electronics. They allow the engine management system to monitor and adjust performance. Here are the most common malfunctions:

1.1. Faulty Camshaft Position Sensor

The camshaft position sensor measures the rotation speed of the camshaft and sends the data to the ECM (Electronic Control Module). If this sensor is defective, the timing of ignition and fuel injection will be incorrect, leading to a loss of power.
Solution: An electronic diagnostic can confirm the problem, and replacing the sensor is relatively inexpensive.

1.2. MAF (Mass Air Flow) Sensor

The MAF sensor measures the amount of air entering the engine. A malfunction leads to poor management of the air/fuel mixture, which reduces performance.
Solution: Clean or replace the MAF sensor depending on its condition.

1.3. Faulty Oxygen Sensor

This sensor, located in the exhaust system, measures the amount of unburned gases and adjusts the air/fuel ratio accordingly. A faulty sensor leads to inefficient combustion and increases fuel consumption.
Solution: Replace the sensor and perform an emissions check.

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2. Actuator Malfunctions

Actuators physically control the mechanisms essential for the proper functioning of the engine.

2.1. Worn Spark Plugs

End-of-life or dirty spark plugs prevent proper combustion, which reduces power.
Solution: Replace them regularly according to the manufacturer’s recommendations.

2.2. Faulty Ignition Coil

The ignition coil transforms the 12-volt current into high voltage to power the spark plugs. A failure leads to misfires.
Solution: Have the coil tested and replaced if necessary.

2.3. Clogged or Faulty Fuel Injectors

Injectors spray fuel into the engine. A clogged injector reduces the amount of fuel, leading to a loss of power and misfires.
Solution: Have the injectors cleaned or replaced.

2.4. Weak Fuel Pump

The pump must maintain sufficient pressure to supply the engine. A faulty pump causes acceleration difficulties and intermittent breakdowns.
Solution: Check the fuel pressure and replace the pump if necessary.

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3. Mechanical Failures

Mechanical problems are often related to wear and tear or neglected maintenance.

3.1. Clogged Fuel Filter

The fuel filter prevents impurities from entering the engine. A dirty filter limits the fuel supply, leading to a drop in performance.
Solution: Change the filter every 20,000 to 40,000 km according to the manufacturer’s recommendations.

3.2. Clogged Air Filter

A dirty air filter prevents air from reaching the engine, affecting combustion.
Solution: Replace or clean the filter regularly.

3.3. Blocked Exhaust Pipe

A clogged catalytic converter or muffler limits the evacuation of gases, reducing power.
Solution: Check the components of the exhaust system and clean or replace them if necessary.

3.4. Low Compression

Cylinder compression is essential for combustion. Problems such as a faulty head gasket, leaking valves, or worn piston rings reduce compression.
Solution: A compression test can identify the problem. Depending on the severity, it may require costly repairs.

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Addition: Importance of Preventive Maintenance

Many of the problems mentioned here can be avoided through regular maintenance. Here are some tips to prevent power loss:

• Check and replace fuel and air filters according to the maintenance schedule.
• Clean critical sensors such as the MAF sensor.
• Have your engine diagnosed at the first signs of power loss, such as misfires or irregular acceleration.

By taking care of your car and monitoring warning signs, you can extend the life of your engine and avoid costly repairs.

Hydraulic Lifters: Operation, Failures, and Solutions

Hydraulic lifters play a key role in the proper functioning of your engine. Located near the valves, these small cylinders ensure smooth and quiet operation. However, over time and with a lack of maintenance (dirty oil, insufficient pressure), they can wear out and generate a tapping noise.

Ignoring these noises or other signs of malfunction can lead to serious and costly damage. To avoid this, here is everything you need to know about hydraulic lifters: their operation, symptoms of failure, and solutions to fix them.

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1. Operation of Hydraulic Lifters

Hydraulic lifters are connected to the valves by a small rod called a rocker arm. Unlike mechanical lifters, they contain oil that activates a piston and a spring, thus allowing optimal clearance in the valve train and reducing engine wear.

However, low oil pressure can affect their performance and cause unusual noises. If this problem is not addressed quickly, it can cause damage to the valves, rocker arms, and pushrods, making repairs expensive.

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2. Symptoms of a Faulty Hydraulic Lifter

A faulty lifter is recognized by a constant tapping noise that worsens over time. Depending on the severity of the problem, this noise can be noticeable both when cold and when hot.

Common Causes of Failure:

• Sticking check valve
• Lifter clearance issues
• Dirt buildup or excessive wear
• Lack of lubrication or contaminated engine oil
• High vehicle mileage
• Irregular maintenance
• Use of inappropriate engine oil
• Clogged or faulty oil filter

Main Symptoms:

1. Sticking Lifters

A sticking lifter remains collapsed, preventing the system from maintaining oil pressure and generating a clattering noise.

2. Noise Amplified with Increased RPM

A faulty lifter produces a louder and more frequent noise as the engine speed increases.

3. Engine Misfires

A faulty lifter disrupts the air/fuel mixture, causing misfires and a loss of power.

4. Dead Cylinder

A mispositioned pushrod can lead to a non-functioning cylinder, risking serious engine damage.

5. Check Engine Light On

Advanced lifter failure can trigger the check engine light. In this case, diagnosis via error code is recommended.

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3. Solutions and Preventive Maintenance

Replacing Hydraulic Lifters

An engine typically has two lifters per valve. Depending on the extent of the damage, it may be necessary to replace between 2 and 32 lifters. Add to that the cost of gaskets, bolts, and other parts, and the repair can become expensive.

An alternative is to purchase a complete replacement kit, often more economical than buying individual OEM parts. Although remanufactured lifters may seem attractive, they do not reduce labor costs and are generally not recommended.

How to Reduce Lifter Noise?

1. Regular Oil Changes
   • Always use the correct engine oil and adhere to recommended oil change intervals.
2. Adding an Oil Additive
   • Additives like Liqui Moly or Marvel Mystery Oil improve oil quality and clean the lifters.
3. Adjusting Lifter Clearance
   • If the noise persists, a mechanic can adjust the gap between the lifters and other engine components.

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Conclusion

By paying attention to the symptoms of a faulty hydraulic lifter, you can avoid costly repairs and extend the life of your engine. If you hear suspicious noises, do not delay in taking action. Proper maintenance and appropriate adjustments help prevent major failures and ensure optimal engine operation.

Single and double overhead camshafts have been part of automotive, marine, motorcycle, and aircraft engines since the early 20th century.

Some of the earliest cars with a single overhead camshaft (SOHC) were the 1902 British-designed Maudsley and the 1903 American Marr Autocar.

Double overhead camshafts (DOHC) appeared in a French Peugeot that won the 1912 French Grand Prix.

Overhead cam engines graced a number of military aircraft from World War I. Many of these engine models used shafts to drive the cams. Modern chain-driven overhead camshafts followed in popular automobiles of the 1920s.

DOHC engines gained popularity for many automotive brands after World War II, including Fiat and Alfa Romeo. Today, single and double overhead cam designs proliferate in our domestic and foreign-built cars. Read on to see how SOHC and DOHC engines compare as well as the cam-in-block engine.

The Purpose of the Camshaft

Today’s automotive piston engines use one or more camshafts to operate the intake and exhaust valves. The camshaft is driven by the engine’s crankshaft using a chain or belt that coordinates the timing of the intake and exhaust valves.

These valves admit air and fuel into the combustion chambers and allow the burned mixture to be expelled to the exhaust system.

What is a SOHC Engine?

First, both SOHC and DOHC engine models are overhead valve configurations.

A single overhead camshaft engine uses one camshaft located above each bank of cylinders. For a “V” design engine such as a V6 or V8, there would be two such camshafts, one above each cylinder bank. The camshaft would be driven by a timing chain or toothed timing belt.

At the engine designer’s choice, a number of methods could be used to operate the valves from this single camshaft. If, for example, all valves were aligned parallel to the length of the cylinder head, the cam could operate them all directly. For other valve arrangements, rocker arms or sometimes very short pushrods may be used.

SOHC Advantages

The SOHC design offers several advantages over the cam-in-block design:

• Valves can be positioned for an optimal combustion chamber design. Multiple valves can be used; up to five per combustion chamber are possible. Dual spark plugs can also be used. These improvements can enhance air-fuel flow and combustion capabilities, offering increased power and better fuel economy.
• Passages through the engine block and cylinder head for pushrods are not needed. Both areas can thus use additional (or larger) coolant passages improving cooling efficiency. Improved cooling, particularly in cylinder head areas, can allow for higher compression ratios. This benefits both power and fuel economy.
• The mechanism actuated by the camshaft to open the valves can be both simpler and lighter. This reduces the possibility of valve float making much higher engine speeds possible. Higher engine speeds in general improve power output.
• Access to all valve system components, especially the camshaft, is simpler. Repairs to this critical engine area would then be less costly.

SOHC Disadvantages

SOHC engines have some disadvantages compared to cam-in-block designs as well as DOHC designs:

• Engine complexity is increased. This adds to design and manufacturing cost. There may also be an overall increase in engine weight compared to cam-in-block designs. Camshaft drives using a chain or belt can introduce reliability and maintenance considerations that are not common to cam-in-block engines.
• The engine may become larger and require increased hood height for clearance. Due to the increased engine size, weight may also increase.
• Variable valve timing is largely limited to timing changes for the intake and exhaust valves simultaneously. This is the same timing issue that exists for cam-in-block engines.

What is a DOHC Engine?

A double overhead camshaft engine will have two camshafts located above each row of cylinders. A “V” design engine such as a V6 or V8 would have a total of four camshafts. As with the SOHC engine design, the DOHC would use timing chains or a toothed timing belt to drive the camshafts.

In most cases, with a DOHC (or dual cam) engine, each cam would directly actuate its associated valves.

DOHC Advantages

DOHC engines share the same advantages as SOHC designs. These include:

• Valves can be positioned for an optimal combustion chamber layout. Optimizing the valve layout can benefit power and fuel economy.
• The cooling efficiency of the engine block and cylinder head is improved with DOHC designs. Increased compression ratios offer increased power and energy efficiency.
• DOHC designs offer the most direct valve operation. Peak engine speeds of 8,500 or more are possible for street cars. Racing vehicles can achieve even higher engine speeds with advanced DOHC systems.
• Maintenance access to the camshafts and lifters is easier. This can help reduce overall maintenance and repair costs.
• DOHC engines offer the best of VVT benefits. Variable valve timing can operate independently for each camshaft, providing optimal valve timing for both intake and exhaust valves.

DOHC Disadvantages

As with SOHC engines, DOHC designs share the same fundamental disadvantages.

• Engine complexity and weight are increased compared to cam-in-block designs. Design and manufacturing costs are also higher. Compared to SOHC designs, DOHC engines have a more complex chain or belt drive system. This decreases overall reliability and increases maintenance expenses.
• As with SOHC designs, the DOHC engine height is increased and the total weight also tends to be higher.

What is a Cam-in-Block Engine?

The majority of engines in American cars built just after World War II were cam-in-block models. These used a single camshaft located inside the engine block. This camshaft directly actuated the valves of several popular flathead engines.

For high-performance overhead valve (OHV) engines (engines with valves located above the combustion chambers), the camshaft actuated each valve via a system of pushrods and levers called rocker arms.

Cam-in-Block Advantages

The main advantages of cam-in-block valve systems are:

• Such systems were simple and economical to design and manufacture.
• They proved to be very reliable.
• Cam-in-block engines have a relatively low overall height. This allows for lower hood profiles which can be a boon for sleek body designs.

Cam-in-Block Disadvantages

Cam-in-block designs have some disadvantages, particularly for OHV engines:

• Space allowances for pushrods through the engine block and for rocker arms on top of the cylinder head can dictate or crowd the location of other components.
• The geometry of the pushrod and rocker arm can force inefficient cylinder head combustion chamber shapes and sizes.
• The mass (or weight) of the mechanism between the camshaft and each valve introduces inertia effects that limit valve operating speed. At very high engine speeds, for example above 7,000 revolutions per minute (RPM), the valves may not close completely. This is called valve float which will always limit engine power.
• Pushrods require passages upward through the engine block and cylinder heads. Such passages can restrict the size of cooling areas in the engine block and cylinder heads, tending to degrade cooling efficiency.
• Independent variable valve timing (VVT) that can enhance performance and fuel economy would be difficult to provide for both intake and exhaust valves.

Some of today’s very high-performance engines remain cam-in-block designs. These designs may include some form of variable valve timing. However, cam timing variations would be simultaneous for intake and exhaust valves since these engines have only a single camshaft.

How Can You Tell If You Have SOHC or DOHC?

Generally, you can simply open your car’s hood and examine the top of the engine. A narrow but tall engine top with a distinct bump at the front for the cam drive sprocket usually indicates an SOHC is hidden underneath.

A wide engine and/or a two-humped top will reveal the presence of a DOHC configuration. If in doubt, an online search for your car’s make, model, year, and engine displacement should provide clarification in this regard.

Can You Change SOHC to DOHC?

Making such a change would, in general, be extremely costly. However, some car makes and models have similar engine choices in both SOHC and DOHC configurations. Some Honda models fit this mold.

For specific models, an SOHC cylinder head may be replaced with a DOHC cylinder head. And with proper reprogramming of the engine control unit (ECU) and changes to auxiliary engine systems (as well as good DIY skills), such a transition is certainly possible.

Few circumstances can ruin a day as quickly as the sudden appearance of a strange noise while driving. When it comes to vehicles, strange noises manifest in all manners and frequencies, often leaving the driver unaware of what they heard or where it came from.

If prominent enough, strange vehicle noises can be quite exasperating and very frustrating to diagnose. Some of the most common, yet aggravating, irregular vehicle noises are those that present a whining or droning noise during acceleration.

In truth, there are many potential causes for this type of sound alone, which usually requires extreme attention to detail during the diagnostic process.

Read on to learn more about what to do if your vehicle starts emitting whining noises, as well as the potential causes of these sounds.

Common Causes of Whining Noise When Accelerating

There are quite a few potential causes for your vehicle’s whining noise, many of which are frequently heard by countless motorists on an annual basis. Here are some of the most common causes of vehicle whining during acceleration.

• Internal transmission problems
• Worn alternator bearings
• Damaged water pump bearings
• Low power steering fluid
• Faulty A/C compressor
• Idler pulley/tensioner problems
• Dry, cracked, or slipping serpentine belt
• Worn wheel bearings

What follows is a more in-depth explanation regarding the individual causes of vehicle whining listed above. For simplicity’s sake, these causes have been subdivided into four distinct categories.

#1 – Transmission Issues

A vehicle’s transmission performs an extremely vital function and is essential for distributing engine power to the drive axles of a car, truck, or SUV. Unfortunately, transmissions are prone to internal failures with age.

In some cases, a failure of this nature can present an audible whining noise. Noises of this type can often prove difficult to locate, especially when they resonate from a vehicle’s transmission tunnel.

A whining noise from your vehicle’s transmission typically indicates a fluid-related problem. It is quite common to hear a noise of this nature when a transmission’s fluid level is reduced beyond its capacity or when a transmission fluid pump begins to fail.

Additionally, a failing torque converter can also present a whining noise. Internal bearing wear often presents a roaring noise, which can be mistaken for a whine at high speeds.

Severity

In most cases, the appearance of a whining noise from a vehicle’s transmission is considered quite serious by nature. In the case of a faulty torque converter, replacement will require the removal of the transmission.

The cost associated with such repairs is often high and typically exceeds $1,000. If a faulty internal bearing is to blame for your transmission’s noise, the associated repair cost will be exponentially higher.

#2 – Bearing Wear of Belt-Driven Components

A vehicle’s engine has many belt-driven accessories. Each of these accessories uses a drive pulley, as well as one or more sets of bearings.

A serpentine belt transfers rotational force from the crankshaft pulley to the pulleys associated with various additional belt-driven accessories. These accessories include a water pump motor, power steering pump, A/C compressor, and the alternator. Additionally, systems of such design also feature tensioners and idler pulleys.

When the bearings associated with any of the aforementioned components begin to fail, a whining noise is often heard. The most relevant example of this situation perhaps presents itself in the form of an alternator with bad internal bearings. When these bearings fail, a loud whining or screeching noise can be heard over the sound of typical engine operation.

Power steering pumps also tend to present a fair amount of noise with sufficient wear. Alternatively, one can expect to hear such sounds when a power steering pump is low on fluid.

Severity

Faulty accessory drive components also require prompt diagnosis and replacement. Failing to address these issues can lead to seized bearings and a shredded belt, ultimately leaving you stranded on the road.

Since most modern vehicles rely on a single serpentine belt to drive all associated accessories, a single locked-up component can render the rest of a vehicle’s belt-driven accessories unusable.

#3 – Dry, Cracked, or Slipping Serpentine Belt

As mentioned above, a vehicle’s serpentine belt drives a number of components that are essential to the vehicle’s operation. However, a belt can only drive these accessories if it is in optimal shape.

Over time, a serpentine belt can begin to dry out and crack. As a result, a belt is unable to grip the pulleys of the various accessories it drives as effectively as desired. This inevitably leads to belt slippage, the severity of which only increases over time.

As a serpentine belt slips along the outer diameter of various pulleys, the resulting friction can produce a significant amount of noise. These sounds are perhaps best described as a whining or squealing noise, which tends to increase in intensity during acceleration. This additional friction can also further damage an already worn serpentine belt, ultimately leading to failure.

Severity

In many cases, the whining or squealing of a serpentine belt is more of a nuisance than anything else and carries little risk of creating additional problems if not addressed immediately.

However, a severely worn or damaged serpentine belt can break or be thrown from the pulleys it rides on. When this happens, the function of all belt-driven accessories will be compromised, ultimately leaving you stranded.

#4 – Worn Wheel Bearings

Wheel bearings have the responsibility of ensuring that our vehicles’ wheels rotate freely as they travel down the road. These bearings are often contained within a unitized hub, which must be replaced if the bearings housed within begin to wear out.

Alternatively, many older vehicles featured independent wheel bearings, which could be removed and repacked with grease if necessary. Unfortunately, regardless of type, wheel bearings tend to wear out over time.

In the vast majority of cases, a severely worn wheel bearing will make a roaring noise as a driver moves down the road. This noise typically changes pitch as the vehicle accelerates. At high speed, this sound often resembles a droning or whining noise.

One can often identify a faulty wheel bearing during turns. If the sound in question changes pitch or ceases altogether mid-turn, a vehicle’s wheel bearings become suspect.

Severity

Excessively worn or damaged wheel bearings should be replaced as soon as possible. Failing to do so will only lead to increased wear, further worsening the problem.

When they reach a point of total failure, the rollers found in a wheel bearing’s cage can dislodge and come loose, creating a dangerous amount of free play in a vehicle’s hub.

In the most extreme cases, an excessively worn wheel bearing can cause a hub to rest freely on its axle. This presents a dangerous situation, which can ultimately cause a wreck or severely damaged wheel end components.