How often should I change my engine oil?

Change it when your car's service schedule says, in miles or months, whichever comes first. For many cars that means once a year, and cars on flexible servicing can go longer between changes. If most of your driving is short trips, towing or stop-start traffic, change it more often.

Your handbook or service book gives the interval for your car, and so does Find My Oil from your registration.

What do normal, severe and flexible servicing mean?

• Normal: the standard interval in your handbook, for everyday mixed driving.
• Severe: a shorter interval for harder use, such as mostly short journeys, towing, stop-start traffic or dusty roads.
• Flexible: sometimes called longlife or variable servicing. The car works out when the oil needs changing from the way it is driven, and tells you on the dashboard. It needs an oil that meets the longlife specification in your handbook.

Find My Oil shows your car's interval under each of these, in miles and months.

Why does engine oil need changing?

Oil wears out as it works. Its additives get used up, it picks up soot, fuel and moisture, and it slowly loses its ability to protect the engine. Topping up adds fresh oil but leaves the old oil and dirt in the engine, so it is no substitute for a change.

I hardly drive. Do I still need to change it every year?

Yes. Oil ages even when the car isn't used, and short trips are hard on it, because the engine rarely gets hot enough to drive off moisture and fuel. That is why service schedules give a time limit as well as a mileage.

Should the oil filter be changed too?

Usually, yes. Most service schedules change the filter with the oil, so fresh oil isn't run through a filter full of old dirt. Your service book says what your car needs.

What should I check between changes?

The oil level, about once a month and before a long journey. Most engines use a small amount of oil between services. Our guide to checking your engine oil level shows how, step by step.

Questions

Does dark oil mean it needs changing?

Not on its own. Oil darkens soon after a change as it carries dirt away from the engine. Go by your service interval, not the colour.

Can I change my own oil?

Yes, if you have the tools and somewhere safe to work. Use the grade and specification your handbook gives, which Find My Oil shows along with how much your engine takes. Take the old oil to your local household waste recycling centre; never pour it down a drain.

Does changing my oil myself affect my warranty?

Check your warranty terms. Many ask for servicing on schedule with oil that meets the manufacturer's specification, and for records to show it.