Four kinds of part, and a threefold price difference between them. Knowing which is which is one of the easiest ways to control a repair bill.
The four kinds
| Type | What it is | Price |
|---|---|---|
| OEM | Sold by the dealer in the manufacturer’s box. Identical to what the factory fitted. | Highest |
| Aftermarket | Made by an independent company to fit your car. Quality ranges from excellent to poor. | 30–60% less |
| Remanufactured | The original unit rebuilt with new wear parts, tested to a standard. | 30–50% less than new |
| Used | Pulled from a salvage vehicle. Sold as-is or with a short warranty. | Cheapest |
One thing worth knowing that surprises people: a lot of “aftermarket” parts are made in the same factory as the OEM part. Many manufacturers do not make their own alternators, brake pads or water pumps — they buy them from suppliers like Bosch, Denso, Aisin or Brembo, who also sell the same component in their own box for less. That is called OE-equivalent, and it is usually the sweet spot.
When the cheap part is fine
Aftermarket is a sound choice for most routine work — brake pads and rotors, filters, belts, hoses, batteries, wiper blades, suspension components, radiators, water pumps. Buy a name you recognise rather than the cheapest thing on the shelf and you will not notice a difference.
Remanufactured is the sensible default for alternators and starters. These are rebuildable by nature, the reman industry for them is mature, and the big chains often back them with a lifetime warranty. Paying dealer price for a new alternator is rarely worth it.
Used makes sense for body panels, mirrors, glass, interior trim, wheels and light housings — things that either work or visibly do not, where there is no hidden wear to worry about. A used door mirror at $60 instead of $280 is a good trade.
When to pay for OEM
- Anything electronic that talks to the car’s computers — sensors, control modules, some ignition coils. Aftermarket versions are the most likely to behave oddly or throw codes.
- Safety-critical restraint parts — airbags, seatbelt components. Not a place to economise, and counterfeits genuinely exist here.
- Anything where the fit has to be exact — timing components, some gaskets, parts on European cars where aftermarket support is thin.
- A car still under warranty, where a non-OEM part on a related system could become an argument.
- A part you have already had fail once in aftermarket form.
Core charges, briefly
Remanufactured parts carry a core charge — a deposit, typically $15 to $25 on a battery and $40 to $100 on an alternator or starter, refunded when the old unit goes back to the supplier.
If a shop does the work, they keep and return the core, so the core charge should not appear on your bill as a cost. If it does, ask. And if you asked for the old parts back, that is the one legitimate reason a shop will say no — a core has to go back.
What to ask
- “What brand is going on, and is it OEM, aftermarket or reman?”
- “Is there a cheaper option that you’d still be happy to warranty?” The second half of that sentence is what makes it a good question.
- “What’s the warranty on the part itself?”
Under Illinois law the written estimate has to describe the parts and state whether they are new or used, so this is information you are entitled to rather than a favour.
Checking the markup
Shops buy parts at trade price and sell them at retail or a little above. That margin is a legitimate part of how a shop stays open, and it pays for the warranty they put on the part.
Search the part name and your car to see roughly what it sells for. A modest markup over retail is normal. Three times retail is a question worth asking.
What to watch out for
- Aftermarket parts billed at OEM prices. The estimate has to describe what is going on the car — check the invoice matches.
- “We only use OEM” presented as a quality guarantee when it is really a pricing policy. Often at dealers, and sometimes genuinely justified — but ask whether an equivalent exists.
- Counterfeit parts. Rare at established shops, more common with unusually cheap online sellers of brand-name brake and safety components.
- The cheapest quote in town. Sometimes it is efficiency. Sometimes it is the bottom-shelf pad that will squeal in four months.
A plain-language summary, not legal advice. See the disclaimer.