Blue smoke from the exhaust
Blue or blue-grey smoke means the engine is burning oil.
AreaExhaust & smells
UrgencyModerate
Can I keep driving? Drivable with care. Diagnose soon: performance, economy or other components can be affected.
Common causes
Worn valve stem seals
Puffs of blue smoke at start-up or after idling.
Worn piston rings
Smoke under acceleration, high oil consumption.
Turbocharger seal failure
Oil leaks into the intake or exhaust; often with oil in the intercooler hoses.
Blocked PCV system
Crankcase pressure pushes oil past seals.
Overfilled engine oil
Too much oil can be churned and drawn into the intake.
What to check
- Check the oil level and consumption over a measured distance.
- Note when the smoke appears: start-up, acceleration or deceleration.
- Inspect the PCV valve and hoses.
- Do a compression and leak-down test.
Related OBD2 codes
Repair guides
Other exhaust & smells problems
General guidance only. A qualified technician can confirm the cause; brakes, steering and fuel leaks should be checked professionally if in doubt.