What is blow by on a diesel?

Blow by in a diesel engine refers to the phenomenon where combustion gases and unburned fuel escape past the piston rings and into the crankcase. This can happen due to wear on the piston rings, cylinder walls, or valve seals, among other factors.

Excessive blow by in a diesel engine can lead to a number of issues, including decreased engine performance, increased oil consumption, and contamination of the engine oil with fuel and combustion by-products. It can also contribute to increased emissions and reduced fuel efficiency.

To address blow by in a diesel engine, it is important to regularly check and replace worn piston rings, valve seals, and other components that may be contributing to the issue. Additionally, using high-quality engine oil and performing regular oil changes can help reduce the buildup of contaminants in the crankcase.