How often should you change your engine oil?

Old oil loses lubrication and can seize an engine.

Degraded oil stops carrying heat away and stops holding contaminants in suspension, so deposits form. On modern turbocharged engines that means coked oil in the turbo bearing, and on engines with variable valve timing it means blocked oil control passages. Both are expensive, and both start as a skipped service.

1. Warm the engine briefly, then stop it. Warm oil drains far more completely than cold oil. Two or three minutes is enough, and it avoids scalding.
2. Raise and support the car properly. Axle stands or ramps. Never work under a car held up by a jack alone.
3. Drain from the sump plug. Position the pan, remove the plug, and let it drain fully. Replace the crush washer rather than reusing it.
4. Change the filter. Cartridge or spin-on. Smear clean oil on the new seal, and hand-tighten only. Over-tightening is how seals fail.
5. Refit the plug to torque. Use a torque wrench. A stripped sump thread turns a cheap service into a new sump.
6. Refill with the correct specification. Match the manufacturer’s viscosity and specification, not just the grade. Modern engines are specific about this.
7. Check level, run, then recheck. Fill slightly short, run for a minute, let it settle, then top to the mark. Check underneath for leaks.
8. Reset the service indicator. And take the old oil to a recycling point. Pouring it away is illegal everywhere.

• The service light or oil life monitor reaching zero
• Oil on the dipstick that is black and thin rather than amber and viscous
• A ticking or rattling on cold start that fades as pressure builds
• Oil level below the minimum mark, which is a separate and more urgent problem

• Using the wrong specification oil because the viscosity matched: modern engines with particulate filters need low-SAPS oil, and the wrong oil damages the filter
• Reusing the sump plug washer, which is the usual cause of a slow weep afterwards
• Over-tightening the filter, which distorts the seal
• Following a 10,000 mile interval while doing short urban trips, which is exactly the condition that dilutes oil with fuel

• Short journeys where the engine never fully warms are far harder on oil than motorway miles
• Towing, track use and extreme heat all shorten it
• Direct injection and turbocharging both increase fuel dilution
• Time matters as well as distance: oil in a lightly used car still degrades, so change annually regardless

If oil pressure warning lights come on, stop the engine immediately and do not restart it. That is not a service interval question.