Diesel car owners often face significant carbon deposit buildup and occasional engine contamination. The reason your vehicle’s engine behaves this way is blow-by in a diesel engine. Now you must be wondering what blow-by is in a diesel engine, right? Well, it’s not an ordinary issue but a drastic problem that can diminish the vehicle’s engine performance. Several causes are responsible for this behavior of your car’s engine.
So, let’s understand why the diesel engine behaves this way and what blow-by gas means:
What is Blow-by in a Diesel Engine? Causes and Solutions
A serious issue affects engine operation when a cylinder wall and piston have a faulty seal, allowing the air-fuel mixture to leak into the engine crankcase. This is what we call blow-by gases in a diesel engine. Possible causes of this problem can be poor performance, reduced torque and power, or even higher oil consumption. It’s always advisable to follow effective maintenance tips from experts for better understanding. Now let’s see what causes it and how it affects the vehicle.
What Causes Blow-by in a Diesel Engine?
Blow-by is a phenomenon that creates unwanted pressure waves; this process often generates unusual sounds and can damage certain moving parts inside the engine like a cylinder or piston. We often encounter this issue in gasoline engines; nevertheless, diesel engines always have this problem due to the high compression ratio.
Typically, blow-by occurs at the end of compression, at the beginning of combustion, when the spark plug hasn’t ignited yet and the air mixture in the car has spontaneously ignited. For diesel engines, fuel burns in many combustion areas. So, what are the causes of this problem:
1. Worn Pistons
One reason that can answer your question about what blow-by is in a diesel engine and what causes it is worn pistons. Unlike cylinder walls that amplify wear, pistons tend to become smaller. Since aluminum is a soft metal, it easily allows buildup in the combustion chamber and creates grooves in the piston. And this means the air-fuel mixture will accumulate in the crankcase.
2. Damaged Cylinder Walls
Another possible reason leading to blow-by in a diesel engine is damaged cylinder walls. With continuous use, the vehicle and its components wear out. This also includes cylinder walls. Continuous piston and piston ring scraping lead to damage to cylinder walls.
This creates a gap in the cylinder, enlarging it, which makes it easier for compressed gases to pass into the piston. We hope these points help you understand what diesel blow-by is. Worn cylinders can never function as they should. So it’s always recommended to keep an eye on the cylinder.
3. Broken Piston Rings
The third reason could be those broken piston rings. When looking for an answer to the question “what does blow-by mean in a diesel engine,” it’s important to mention this point. Broken or damaged piston rings can cause blow-by in a diesel engine. The incessant friction of the rings in the cylinder eventually damages it. The sealing capabilities of the piston ring can be expected to deteriorate significantly over time. This certainly leads to gases easily seeping behind the ring, which simply results in blow-by in a diesel engine.
Solutions for Blow-by in a Diesel Engine
Excessive smoke, decreased engine performance, or higher oil consumption can be the result of blow-by in a diesel engine. So, how can we fix this phenomenon? The steps below can help:
Check the PCV System:
The PCV, or Positive Crankcase Ventilation, is responsible for regulating crankcase pressure. If you notice a leak or a hose on the PCV system, you need to replace it to solve the problem.
Inspect and Change Piston Rings:
Faulty or worn piston rings are the most common reasons causing blow-by. The consequence is that the rings don’t create a proper seal and gases can’t escape. In this case, we recommend changing the piston rings, but it’s a rather complex task and you should entrust your car to a qualified mechanic to repair it.
Inspect Valve Seals and Cylinder Head:
Inspect the cylinder head for any signs of damage or warping. Damaged cylinder heads can cause blow-by. Additionally, worn valve seals can allow gases to bypass the piston rings. Replace faulty components if necessary.
The Crucial Point
We believe you may now have an answer to the question of what blow-by is in a diesel engine and what causes it. So it’s recommended to keep an eye on the piston, piston rings, and even the cylinder to ensure your vehicle operates properly.