Manufacturer "acceptable" oil consumption is shockingly high — many UK car makers consider up to 1 litre per 1,000 miles "within tolerance". Anything significantly above that is a real problem.
What's normal?
- Modern petrol: less than 0.5L per 6,000 miles is normal - Modern diesel: less than 0.5L per 6,000 miles is normal - High-mileage engines (120,000+): up to 1L per 3,000 miles - Known oil-burners (BMW N47, Audi 2.0 TFSI EA888 Gen 1/2, Mini N18, VW 1.4 TSI): up to 1L per 1,000 miles "per spec"
Where the oil is going
1. **Burning** — blue smoke on startup or under load (valve stem seals, piston rings) 2. **Leaking** — drips on the drive (rocker cover, sump, crankshaft seals) 3. **Crankcase ventilation fault** — sucking oil into the inlet (PCV valve failure) 4. **Turbo seals** — oil into the exhaust, blue smoke under boost
UK repair costs
- PCV valve/oil separator: £180–£500 - Rocker cover gasket: £180–£350 - Valve stem seals: £400–£900 - Piston ring replacement: £1,500–£3,500 - Turbo replacement: £900–£2,400
Can additives stop oil burning? — Thicker oil (10W-40 instead of 5W-30) can slow consumption short-term but isn't a fix. Use only the manufacturer-spec oil long-term.
Will it fail the MOT? — Visible blue smoke on the emissions sniff test is an MOT failure.
Bob's Mechanical Repairs — independent family-run garage in Birnam, Dunkeld, Perthshire. Call 01350 727 276 or email bob@bobsmechanicalrepairs.co.uk.