How it happens:
* Blow-by: During combustion, a small amount of the burning fuel-air mixture (which includes unburnt fuel) can escape past the piston rings and into the crankcase. This is known as "blow-by."
* Vaporized fuel: Some fuel may also evaporate into the crankcase from the fuel system, particularly during hot conditions.
Why it's a problem:
* Dilution: The gas (unburnt fuel) can dilute the engine oil, reducing its viscosity and lubricating properties. This can lead to wear and tear on engine components.
* Increased wear: Diluted oil can't effectively lubricate the engine, leading to increased friction and wear on bearings and other moving parts.
* Detonation: In extreme cases, a large amount of unburnt fuel in the crankcase can cause detonation (knocking) in the engine.
How to prevent it:
* Proper engine maintenance: Regular oil changes and using the correct viscosity oil help to mitigate the effects of blow-by.
* Good piston ring condition: Worn or damaged piston rings allow more blow-by. Maintaining good ring condition is essential.
* Proper fuel system: Leaking fuel injectors or other fuel system issues can contribute to fuel vaporizing into the crankcase.
In summary: While it's not "gas" itself going into the crankcase, unburnt fuel and fuel vapors can enter the crankcase due to blow-by. This dilution of the engine oil is a problem that needs to be addressed.
