- Reduced engine power: The combustion gases that leak past the piston rings can reduce the amount of power that the engine produces.
- Increased oil consumption: The combustion gases that leak into the crankcase can mix with the oil, causing it to become diluted. This can lead to increased oil consumption.
- Rough idling: Excessive blow-by can cause the engine to idle rough.
- Engine damage: In severe cases, excessive blow-by can damage the engine components, such as the piston rings, cylinder walls, and crankshaft.
There are a number of factors that can contribute to excessive blow-by, including:
- Worn piston rings: The piston rings are responsible for sealing the combustion gases in the cylinder. When the piston rings are worn, they can no longer seal the gases effectively, leading to blow-by.
- Damaged cylinder walls: The cylinder walls provide a smooth surface for the piston rings to seal against. If the cylinder walls are damaged, it can make it difficult for the piston rings to seal properly, leading to blow-by.
- Incorrect piston ring installation: If the piston rings are not installed correctly, it can lead to blow-by.
- Excessive clearance between the piston and the cylinder wall: If there is too much clearance between the piston and the cylinder wall, it can allow the combustion gases to leak past the piston rings, leading to blow-by.
Excessive blow-by can be diagnosed by a qualified mechanic. The mechanic will typically perform a compression test and a leak-down test to determine the amount of blow-by. If the blow-by is excessive, the mechanic will recommend repairs, such as replacing the piston rings or repairing the cylinder walls.
