Could blue smoke from exhaust be caused by worn valve stem seals?

Oil seeps past the seals and burns. Smoke is worst on startup, then clears.

Could blue smoke from exhaust be caused by worn piston rings?

Oil gets past the rings into the cylinder. Smoke is constant during acceleration.

Could blue smoke from exhaust be caused by pcv valve stuck open?

Cheapest cause to rule out — a stuck PCV pulls oil into the intake.

Could blue smoke from exhaust be caused by turbo oil seal failure (turbocharged engines)?

Turbo bearings leak oil into the intake or exhaust, causing blue smoke.

Blue Smoke From Exhaust

Q: How serious is blue smoke from exhaust?

Severity is rated High. Check oil level frequently. Try a PCV valve replacement first as it's cheap. If that doesn't help, you're looking at engine work.

Blue or gray smoke means the engine is burning oil.

Severity: High

What to Do Right Now

Check oil level frequently. Try a PCV valve replacement first as it's cheap. If that doesn't help, you're looking at engine work.

Common Causes

Worn valve stem seals: Oil seeps past the seals and burns. Smoke is worst on startup, then clears. Shop valve stem seals
Worn piston rings: Oil gets past the rings into the cylinder. Smoke is constant during acceleration. Shop engine
PCV valve stuck open: Cheapest cause to rule out — a stuck PCV pulls oil into the intake. Shop pcv valve
Turbo oil seal failure (turbocharged engines): Turbo bearings leak oil into the intake or exhaust, causing blue smoke. Shop turbocharger