What is diesel blow by?

Diesel blow by is a common issue that occurs in diesel engines, where excess gases and oil vapors escape from the engine's crankcase and into the air intake system. Blow by occurs when there is an increase in pressure within a diesel engine's crankcase, which forces gases to escape through the piston rings and into the combustion chamber.

Some common causes of diesel blow by include worn or damaged piston rings, damaged cylinder walls, and worn valve guides. Contaminants in the engine oil, such as dirt, water, and metal particles, can also contribute to blow by.

Diesel blow by can result in a loss of engine power, increased fuel consumption, and increased emissions. It can also cause damage to other engine components, such as the turbocharger and exhaust system.

Regular maintenance, such as replacing worn piston rings and keeping the engine oil clean and free of contaminants, can help prevent diesel blow by. If blow by is severe, it may require engine repairs or replacement.