1. Worn valve seals: Worn or damaged valve seals allow oil to enter the combustion chamber, causing grey smoke to be emitted from the exhaust.
2. Piston ring: If the piston rings are damaged or excessively worn, oil may leak into the combustion chamber which will be burned along with the fuel mixture resulting in grey exhaust smoke.
3. Faulty turbocharger: A faulty turbocharger can cause oil leakage and if excessive oil is leaking into the combustion chamber, grey smoke will be produced.
4. Poor quality oil: Using low-quality oil can lead to the formation of sludge and carbon deposits in the engine, resulting in grey smoke emission from the exhaust.
5. Insufficient oil pressure: If there is insufficient oil pressure, the oil may not circulate properly, leading to poor lubrication of the engine components, which in turn can cause increased wear, smoke and exhaust smoke.
