People can cut the cost of buying replacement parts for their car by up to 50%, says What Car?. Thanks to a change in the law, motorists can choose where to take their new or used car for a service, and can also specify that cheaper equivalent-quality parts should be used.

What Car? found that while the dealer price for an original-equipment battery to fit a new small family car was £71.66, a big-brand aftermarket part could be bought for £41.94. A set of front brake pads bought from the dealer cost £65.40, compared with £36.60 for a matching-quality pair. An oil filter costing £8.83 from the dealer could be replaced with a matching-quality part for £4.92.

What Car? consumer editor Emma Butcher said: “There is a general misconception that having a car serviced away from a main dealer or using non-car-maker parts will invalidate its warranty. This isn’t the case as long as any replacement part is either the original component, or a part of matching quality**. The part must also be fitted to the car maker’s specification.”

What Car? advises motorists to ask their dealer or garage to help them find the cheapest quality parts first. Car owners who want to shop around should look for parts made by well-known, established and trusted brands.

“It’s always best to ask your dealer or garage to source your parts for you. However, if you are buying them yourself, make sure you deal only with a reputable retailer and are sure of the part’s quality. Car safety is paramount,” said Butcher.

10 tips for buying car parts

  1. Speak to your garage before you check out other sources – they’ll be able to find you the best price and confirm which parts will fit without invalidating your warranty.
  2. Always source parts from reputable companies operating from a registered address; for example, your local parts retailer or a chain such as Halfords.
  3. Check that the company you’re buying from gives you a warranty on the parts, and always read the terms and conditions, particularly the returns policy.
  4. Have your registration number or, even better, the Vehicle Identification Number (VIN) to hand. You can usually find this on the dashboard below the windscreen or on the driver’s side door pillar.
  5. If you do buy your own part, ask your dealer or garage to check its quality and authenticity for you before it’s fitted. Good garages won’t install substandard parts to your car.
  6. Get a trusted dealer or garage to fit the parts. Doing it yourself could invalidate your warranty.
  7. Be wary about very cheap parts. Always ask to see the part’s original-equipment-quality certification.
  8. Keep all your receipts and, to keep your warranty protected, ask your garage to itemise replacement parts fitted to your car on the service record.
  9. When buying online, be cautious about who you’re dealing with.
  10. If you do buy online, check the box for signs of tampering and look for clues to the part’s authenticity, such as spelling mistakes on the packaging.