What Causes Oil in the Intake Manifold?
1 Answers
Reasons for oil in the intake manifold: 1. Prolonged engine idling; dirty air filter; clogged or deformed crankcase ventilation system. 2. Clogged, leaking, or deformed turbocharger oil inlet/return pipes; coking of lubricating oil in the turbocharger's intermediate housing. 3. Cylinder wear causing piston ring blow-by; excessive flow resistance in the exhaust system. 4. Prolonged imbalance between intake pressure and the turbocharger bearing housing pressure, leading to oil leakage from the turbocharger into the compressor due to pressure differential acting on the seals. 5. Overfilling of engine oil increases the unavoidable lubricant content in the crankcase ventilation system, promoting oil entry into the intake pipe through the ventilation system.