How Often Should You Change Your Car's Oil?

Summary

• Most cars need an oil change every 10,000-15,000 miles or once a year, whichever comes first.
• Check your dipstick monthly: It takes 30 seconds and prevents expensive damage.
• Using the wrong oil can cause problems: Always use the grade recommended in your owner's manual.

Oil keeps your engine running smoothly. Without enough clean oil, metal parts grind together. This causes wear, overheating, and eventually engine failure.

Changing your oil on time is one of the simplest things you can do to protect your car. Here's how often and why it matters.

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How Often Should You Change Oil?

It depends on your car and how you drive. Here's a general guide:

Oil Type	Change Interval
Mineral oil	Every 5,000 - 7,000 miles
Semi-synthetic oil	Every 7,000 - 10,000 miles
Fully synthetic oil	Every 10,000 - 15,000 miles
Long-life oil	Every 15,000 - 20,000+ miles

Always check your owner's manual for the exact recommendation. Some modern cars have a service interval indicator that tells you when it's due.

Rule of thumb: If in doubt, change your oil every 10,000 miles or once a year. This suits most UK driving conditions.

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How to Check Your Oil Level

Checking your oil takes less than a minute. Do it at least once a month.

1. Park on level ground and wait a few minutes for the oil to settle.
2. Pull out the dipstick and wipe it clean with a cloth.
3. Reinsert it fully and pull it out again.
4. Check the level. The oil should be between the minimum and maximum marks.
5. Check the colour. Clean oil is amber or light brown. Very dark or gritty oil needs changing.

If the level is low, top it up with the correct grade. If it keeps dropping, there may be a leak — get it checked.

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What Happens If You Don't Change Oil?

Old oil breaks down and loses its protective properties. Over time, this causes:

• Increased engine wear: Metal-on-metal contact damages internal components.
• Sludge build-up: Old oil turns thick and gummy, blocking oil passages.
• Overheating: Oil helps cool the engine. Degraded oil can't do this as well.
• Reduced fuel economy: A struggling engine uses more fuel.
• Engine failure: In extreme cases, the engine can seize completely. This is a very expensive repair — or the end of the car.

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Choosing the Right Oil

Using the wrong oil can cause problems. Your owner's manual specifies the correct grade (like 5W-30 or 0W-20).

The numbers describe the oil's viscosity (thickness) at different temperatures. The first number (with the W) is cold weather performance. The second is hot weather performance.

• 5W-30: The most common grade in UK cars. Good all-round performance.
• 0W-20: Thinner oil used in many modern and hybrid cars. Don't use this if your car needs 5W-30.
• 5W-40: Common in European cars, especially German brands.

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DIY Oil Change or Garage?

An oil change at a garage typically costs £80-£150. A DIY oil change costs £30-£50 for oil and a filter.

If you're handy and have basic tools, DIY is straightforward. But you need to dispose of old oil properly — you can take it to your local recycling centre for free.

Getting it done as part of a regular service makes sense. The mechanic checks other things at the same time. Read our car servicing guide for more details.

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Oil Changes and Your Service History

Oil changes are done at every service. If you keep your car serviced on schedule, the oil is always fresh.

A full service history proves the car has been well maintained. This matters for resale value and buyer confidence.

Missed services show up in the record. Check your car's MOT history for any related advisories.

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Changing your oil is cheap insurance against expensive engine damage. Keep it topped up, change it on schedule, and use the right grade. It's one of the best things you can do for your car's health and longevity.

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