What Causes Engine Oil to Leak from the Exhaust Pipe?

[JacksonFitz]

Engine oil leaking from the exhaust pipe is typically due to malfunctions in the piston, cylinder liner, piston pin, or piston rings. In such cases, it is necessary to locate the damaged components and replace them. Additionally, severe wear or poor sealing between the valve stem and valve guide can create excessive clearance, leading to oil leakage downward, which requires prompt repair. The exhaust pipe is part of the engine's exhaust system, which mainly includes the exhaust manifold, exhaust pipe, and muffler. Typically, the three-way catalytic converter, designed to control engine pollutant emissions, is also installed in the exhaust system. The exhaust pipe generally consists of a front exhaust pipe and a rear exhaust pipe.