After market auto parts can save you real money, but only if you pick the right ones. Some are as good as the original, some are better for a specific job, and some are cheap copies that fail early. The tricky part is that they often look alike on a product page.
This guide explains what aftermarket parts are, how they compare with OEM and used parts, when they make sense and when they don’t, plus 7 proven ways to avoid costly mistakes. If a used original part is the better fit for your repair, you can also send a part request and we’ll look for a match.
What are after market auto parts?
After market auto parts are replacement or upgrade parts made by a company other than the vehicle’s original manufacturer. You’ll also see the word written as one word, aftermarket, and the meaning is the same.
The terms below all describe roughly the same group of products.
- Aftermarket auto parts and aftermarket car parts: the everyday terms for non-original parts
- Car after market parts: a common way people type the search
- Aftermarket automotive parts: the more formal, industry-style term
- Aftermarket replacement auto parts: parts meant to replace a worn or broken original
- Aftermarket performance car parts: parts designed to improve power, handling or looks
Aftermarket parts are made for two main jobs. Replacement parts aim to do the same job as the original at a different price. Upgrade or performance parts aim to do something the original doesn’t, such as a stronger brake kit or a freer-flowing exhaust. For a general background, see this overview of the automotive aftermarket.
After market auto parts vs OEM vs used vs remanufactured
Before you buy, it helps to know what your options are. Each one has a different mix of price, fit and risk.
| Type | What it is | Strengths | Trade-offs |
|---|---|---|---|
| OEM (new) | Made by or for the car’s manufacturer | Exact fit, consistent quality | Usually the highest price |
| After market auto parts | Made by other companies | Lower price, wide choice, sometimes upgrades | Quality and fit vary by brand |
| Used (original) | An original part taken from another vehicle | OEM fit at a lower price | Condition varies, so check the part and the warranty |
| Remanufactured | A used part rebuilt to a standard | Often tested, with a warranty | Cost sits between used and new |
There’s no single best choice among after market auto parts, OEM and used for every part. The right choice depends on the part, the age of your car, how long you plan to keep it and how much risk you’re comfortable with.
Are aftermarket parts as good as OEM?
Are after market auto parts as good as original ones? Sometimes yes, sometimes no. The honest answer is that quality depends on the maker and the part, not on the label “aftermarket.”
Where aftermarket parts can be as good or better
- Well-known brands that supply or match original specs
- Parts built to fix a known weak point in the original design
- Upgrades, such as stronger brakes, suspension or lighting
- Items with wide choice, where competition keeps quality up
Where aftermarket parts can fall short
- Unknown or very cheap brands with no track record
- Body panels with poor fit, which can mean gaps and extra labor
- Electronic and sensor parts, where small differences can cause warning lights
- Parts with no warranty, or a vague one
Look for certification
For some body and collision parts, independent certification gives you a quality signal. The Certified Automotive Parts Association tests and certifies certain aftermarket parts. Certification isn’t available for every part, but when it is, it’s a useful tie-breaker.
Aftermarket replacement auto parts: where they make sense
Among after market auto parts, replacement parts are most useful for common wear items and for older vehicles, where the cost of an original part may not be worth it.
Good fits for aftermarket
- Brake pads, rotors and filters, where many reputable brands exist
- Wipers, bulbs, batteries and belts
- Shocks, struts and suspension parts from well-known brands
- Exhaust components
- Older vehicles, where the repair cost should match the car’s value
Think twice
- Safety systems, such as airbags and restraints. Buy from a source that can document the part’s origin and condition. You can also check your vehicle for open safety recalls by VIN.
- Complex electronics, such as engine control units and sensors, where an exact match matters
- Large, expensive parts, such as engines and transmissions, where a tested used original may be a better value than an unknown aftermarket unit
A good habit is to compare three things for every part: the aftermarket price, the price of a used original and the warranty on each.
Aftermarket performance car parts: what to know first
Aftermarket performance car parts, such as intakes, exhausts, tuners, lowering springs and big brake kits, are popular with enthusiasts. They can be fun and worthwhile, but they come with extra questions.
- Emissions rules. Parts that change emissions equipment may not be legal for road use, and rules vary by state. Check before you buy.
- Warranty. Some modifications can complicate a warranty claim on related parts. Read your policy and ask your dealer.
- Insurance. Tell your insurer about significant modifications. Some policies treat them differently.
- Compatibility. Performance parts often depend on other upgrades. One change can strain other parts.
- Installation. Many need professional fitting and a proper tune.
- Resale. Heavily modified cars can be harder to sell.
As with all after market auto parts, if you’re shopping for aftermarket performance auto parts, buy from established brands, read the fitment notes carefully and keep your receipts and install records.
Will aftermarket parts void your warranty?
In general, using an aftermarket part doesn’t automatically void a vehicle’s warranty in the United States. Federal law, including the Magnuson-Moss Warranty Act, limits a manufacturer’s ability to deny coverage just because a non-original part was used.
There’s an important catch. If the aftermarket part itself causes a failure, the repair of that damage may not be covered. And warranty terms differ, so the safest steps are to:
- Read your warranty booklet before you modify or repair.
- Keep receipts and service records for every part and repair.
- Ask your dealer in writing if you’re unsure about a specific part.
- Choose parts from reputable makers that meet or exceed the original specification.
This is general information, not legal advice, so check your own warranty terms.
7 proven ways to avoid mistakes with after market auto parts
Most bad experiences with after market auto parts come from a handful of avoidable errors. Run through these before you pay.
- Confirm fitment with your VIN. Year, make and model aren’t enough. Engine, trim and build date can change which part fits.
- Match the part number to your original or to the maker’s fitment guide.
- Choose reputable brands, and read recent reviews that mention fit and durability.
- Compare the warranty, not just the price. Ask how long it lasts and what it covers.
- Check the return policy, including who pays return shipping if the part doesn’t fit.
- Look for certification where it exists, especially on body and collision parts.
- Compare against a used original. For large parts, a tested used part may beat an unknown aftermarket one on both price and fit.
If a seller can’t answer questions on fit, warranty or returns, treat that as your answer.
When a used original part beats aftermarket
A used original part can be the better choice when you want exact fit without paying new-OEM prices. It tends to work well for:
- Engines, transmissions and drive components, where fit and reliability matter
- Body parts, such as doors, hoods and fenders, that match your car’s original panels
- Electronics and modules, when the part number and VIN range match
- Older vehicles, where new original parts are discontinued or hard to find
At UsedPartZone, we help you find used parts without calling yards one by one. We don’t run a single lot of cars, so the process starts with your request:
- Fill out the Request Parts form. Add your name, email, phone, ZIP code, the part you need, your make and model, and the year.
- We search for a match. We look for a part that fits your vehicle.
- You get the details before you commit. We send the price, condition and terms so you can decide.
- The part ships to you. Orders ship anywhere in the USA, typically in 3–5 days.
- Your part is covered by a 30-day warranty.
Prefer to talk to a person? Call +1-800-590-1385 or email support@usedpartzone.com.
After market auto parts: quick answers to common search terms
| Search term | What it usually means |
|---|---|
| Aftermarket parts auto parts | Non-original parts for cars, trucks and SUVs |
| Aftermarket automotive parts | The formal term for the same products |
| Car after market parts | A common spelling people type in searches |
| Aftermarket replacement auto parts | Parts that replace a worn or broken original |
| Aftermarket performance car parts | Upgrades for power, handling or looks |
| Aftermarket performance auto parts | The same group, including trucks and SUVs |
| Aftermarket car parts | Everyday term for non-original parts |
FAQ
Are after market auto parts good quality?
It depends on the brand and the part. Reputable makers can match or beat original quality, while unknown cheap brands can fail early. Check reviews, certification and the warranty.
Is aftermarket cheaper than OEM?
Usually, but not always. The gap depends on the part, the brand and the car. Compare the aftermarket price, a used original and the warranty on each before you decide.
Can I use aftermarket parts on a car under warranty?
In general, yes. Using one doesn’t automatically void the whole warranty in the US, but damage caused by the part may not be covered. Check your warranty terms and keep your receipts.
What is the difference between aftermarket and used parts?
An aftermarket part is newly made by a company other than the car’s manufacturer. A used part is an original part taken from another vehicle. Used parts keep original fit, and aftermarket parts can offer new condition and a wider choice.
Are aftermarket performance car parts legal?
Many are, but parts that change emissions equipment may not be legal for road use, and rules vary by state. Check the rules where you live before you buy.
How do I know an aftermarket part will fit?
Use your VIN and match the part number or the maker’s fitment guide. If the seller can’t confirm fitment in writing, choose another seller.
Choosing between after market auto parts and a used original
You now know how after market auto parts compare with OEM and used parts, when they’re a good value and which mistakes to avoid. If a used original part looks like the better fit for your repair, send us your part request with your VIN, ZIP code and the part you need. We’ll search for a match and send the price, condition and warranty terms before you decide.
You can also visit UsedPartZone, call +1-800-590-1385 or email support@usedpartzone.com.
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