"OEM" means Original Equipment Manufacturer — the part identical to what the automaker installed at the factory. "Aftermarket" means any compatible part made by a third party. The debate is old, and the real answer is: it depends on the part. This guide tells you when each is the right call.
Quick comparison
| Criterion | OEM | Aftermarket |
|---|---|---|
| Price | Higher (reference) | Usually cheaper than OEM |
| Part warranty | 1-2 years typically | Varies: 90 days to 3 years |
| Quality | Standardized, predictable | Highly variable by brand |
| Availability | Dealer only (sometimes) | Everywhere, many options |
| Fit | Perfect guaranteed | Generally good, sometimes needs adjustment |
When to choose OEM
- Vehicle under warranty. Some automakers deny claims if the failure is tied to an aftermarket part. Check before installing.
- Safety-critical parts — airbags, ABS modules, wheel sensors, timing chains. The safety margin is worth the price difference.
- Complex electronics — some ECUs, BCMs, smart keys. Aftermarket can have incompatible firmware.
- Visible body panels on a newer car — aftermarket often has small fit imperfections, OEM fits perfectly.
- When the price gap is small — sometimes OEM is only 10-15% more. At that level, take OEM.
When to choose aftermarket
- Common wear parts — brake pads, rotors, filters, spark plugs. Good aftermarket brands are often made in the same factories as OEM parts.
- High-mileage car — on a vehicle nearing the end of its life, paying OEM prices for a common wear part doesn't always make sense.
- Performance parts — aftermarket makers often produce better parts than OEM for certain applications (tires, shocks, performance brakes).
- Reputable brands — several well-known aftermarket brands deliver quality equivalent to or better than OEM.
Traps to avoid
1. Bargain-bin aftermarket
The dirt-cheap generic brand from an unknown supplier? Avoid. Quality is unpredictable and the failure rate at 6 months is high. That's the aftermarket that gives all aftermarket a bad name.
2. "OEM" from a cheap reseller
"OEM" parts at half price on some websites? Sometimes it's legitimate surplus. Sometimes it's counterfeit with an OEM label. Buy OEM from reliable sources: dealership, known store.
3. Aftermarket with vague part numbers
If the seller can't give you the exact part number, it's a red flag. Good aftermarket parts always have a verifiable catalog number.
Our store policy
We sell both — OEM when needed, quality aftermarket for most cases. We refuse generic bargain parts because they come back under warranty too often. Our rule: if we wouldn't install it on our own car, we don't sell it.
Verdict
For 80% of common parts (brakes, filters, plugs, belts), a good aftermarket part is the right call. For the remaining 20% (airbags, complex electronics, active warranty), go OEM. Call us with your situation — we'll tell you straight what makes sense for you.
See also our auto parts in Laval, our mechanic invoice guide, or our glossary for the vocabulary.