Why does my car use so much oil?

Some oil consumption is normal in any engine, but needing to top up more than 1 litre per 1,000 miles is considered excessive. Blue or grey smoke from the exhaust is the clearest sign of oil burning. Common causes are worn valve stem seals (smoke on startup then clears), worn piston rings (constant blue smoke under load), or an oil leak finding its way onto hot engine parts. Turbo seal failure is common on turbocharged engines.

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Likely causes

Likely

Worn valve stem seals

Blue puff of smoke on startup or when lifting off the throttle — common on higher-mileage engines

Possible

Worn piston rings

Consistent blue smoke under load — engine compression test will confirm

Possible

Turbocharger seal failure

Oil leaks past the turbo shaft seals and burns in the exhaust — blue smoke especially on acceleration

Possible

PCV (positive crankcase ventilation) valve fault

Allows oil vapour into the intake system — can be cheap to fix

Possible

External oil leak onto exhaust

Oil drips onto hot exhaust and burns — white/blue smoke and burning smell, check for visible oil on engine

Repairs you may need

Typical cost range: £100–£2000PCV valve: £60–150. Valve stem seals: £300–800. Turbo seal/replacement: £500–1,500. Piston rings: full engine rebuild territory.

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Related questions

This information is a general guide based on common causes of this symptom. Symptoms can have multiple causes and accurate diagnosis requires physical inspection by a qualified mechanic. Always consult a professional before deciding not to repair.