What's wrong with my car? · Buying parts
OEM vs aftermarket parts: which should you buy?
"You need genuine parts" can be good advice or an expensive habit. The honest answer depends on the part. Here's how to tell, and how to see dealer, name brand and budget prices side by side for your own car.
The three tiers
Dealer (OEM)
Made for or by the carmaker and sold in its box: Mopar, GM Genuine and ACDelco, Motorcraft, Toyota Genuine and so on. Exact fit and the original spec. Usually the most expensive, and often the same part the OES brand sells for less.
Name brand
Known aftermarket or OES brands with a track record and a real warranty. For most repairs on a car out of factory warranty, this is the sweet spot: original-level quality, lower price.
Budget
Made to hit a price. Fine for a car you plan to sell soon or a part that is easy to swap, like an air filter or a bulb. A poor bet for brakes, steering and anything that is a big job to replace twice.
Which tier for which part
Worth paying for OEM or a top OES brand
Oxygen and other engine sensors, ignition coils on some engines, TPMS sensors, anything linked to cameras, radar or driver-assist, and electronic modules. Cheap ones can throw codes or not talk to the car at all.
Name brand is usually the smart buy
Brake pads and rotors, struts and shocks, control arms, tie rods, wheel bearings, water pumps, radiators, alternators and starters. Pick a brand with a warranty and you get original-level parts for less.
Budget is fine
Air and cabin filters, wiper blades, bulbs, and similar wear items that take minutes to replace.
How to compare fairly
Compare the same part for the same car. Use your VIN, since one model year can have two or three different brake or suspension parts depending on trim. Then look at three things, not just price: the warranty, whether it comes with the hardware you need (clips, bolts, seals), and whether the seller takes returns. The cheapest part that has to be replaced twice costs more than the right one once.
If your shop is quoting the parts
Ask which tier they are quoting and what brand. A shop using dealer parts on a ten-year-old car isn't wrong, but you should know that's the choice being made for you. If you want to check the numbers on a full estimate, see is my repair quote fair?
Common questions
Are aftermarket parts as good as OEM?
Some are better, some are worse. Many name-brand aftermarket parts come from the same factories that supply the carmaker, sold in their own box. Budget parts are made to a price and often wear out sooner. The brand matters more than the label OEM or aftermarket.
Will aftermarket parts void my car's warranty?
Not just for being aftermarket. Under the federal Magnuson-Moss Warranty Act, a carmaker can't refuse a warranty claim only because you used another brand of part. They can refuse it if they show that part caused the damage. Keep receipts for parts and work.
When should I insist on OEM parts?
Sensors and electronics that talk to the car's computer, parts tied to driver-assist cameras and radar, and anything still under the factory warranty. For a lease you hand back, check the contract, since some require genuine parts.
What does OES mean?
Original equipment supplier: the company that makes the part for the carmaker, selling it under its own brand. Bosch, Denso, Aisin, Akebono and NGK are common examples. It is often the same part as the dealer's for less.
Does my insurance have to use OEM parts?
Not always. In California, an insurer's repair estimate has to say when it lists non-OEM parts, and those parts are supposed to be of like kind and quality. Read the estimate and ask if you are unsure what it lists.
This is general guidance, not advice about your specific car or warranty. When a part is safety related, buy a brand you trust.
Not sure which part you need yet?
Start from what the car is doing: squealing brakes, clicks but won't start, running hot, or the full list of symptoms explained.