- What Are OEM Parts?
- What Are Aftermarket Parts?
- Why Insurers Often Prefer Aftermarket Parts
- Does It Actually Matter Which Parts Are Used?
- Your Rights in California
- How to Know What Parts Are Going Into Your Vehicle
- Which Should You Choose?
- Frequently Asked Questions
You pick up your car from the shop. The damage looks fixed, the paint matches, and everything seems fine. Then three months later, a door panel sits slightly off, or a headlight fogs up faster than it should. In some cases, that comes down to one decision made during the repair: OEM or aftermarket parts.
If your insurer was involved, that decision may have already been made for you — without much explanation. Knowing the difference puts you back in control.
What Are OEM Parts?
OEM stands for Original Equipment Manufacturer. These are parts made by the same manufacturer that built your vehicle, or produced to the exact same specification under license. When a Honda Civic rolls off the assembly line, every panel, bracket, and sensor meets a precise standard. OEM replacement parts meet that same standard.
They're designed to fit your specific make, model, and year without modification. The tolerances are exact. The materials match what the factory used. For structural components especially, that precision matters.
OEM parts typically cost more than aftermarket alternatives. The gap varies by part and vehicle, but it can be significant on newer or luxury models.
What Are Aftermarket Parts?
Aftermarket parts come from third-party manufacturers — not the company that built your vehicle. The quality range is wide. Some aftermarket parts are excellent and meet or exceed OEM specs. Others have fitment issues, thinner materials, or shorter service lives.
The main appeal is cost. Aftermarket parts are generally less expensive, which is exactly why insurers tend to push for them — they reduce the overall claim payout.
A few subcategories are worth knowing:
- LKQ (Like Kind and Quality): Used OEM parts pulled from salvage vehicles. They're original manufacturer parts, but they come with prior wear.
- CAPA-certified aftermarket parts: CAPA (Certified Automotive Parts Association) certification means a part has been independently tested against OEM standards. Not all aftermarket parts carry this.
- Non-certified aftermarket parts: No independent quality verification. These carry the most risk.
Why Insurers Often Prefer Aftermarket Parts
Insurance companies have a financial incentive to keep claim costs down. Aftermarket parts cost less, so they show up in estimates more often than most drivers realize. In California, insurers are required to disclose when non-OEM parts are specified in a repair estimate — but that disclosure can be easy to miss if you're not looking for it.
This is where your choice of shop matters. A shop operating under a direct repair program (DRP) agreement with your insurer has agreed to follow that insurer's repair guidelines, which often include using aftermarket parts to control costs. The shop's relationship with the insurer shapes what goes into your vehicle.
At Emfix Collision, we don't operate under any DRP agreements. We're not bound by an insurer's parts preferences. When we review your repair, we look at what your vehicle actually needs — and we tell you exactly what that is.
Does It Actually Matter Which Parts Are Used?
For cosmetic panels on older vehicles, a quality aftermarket part may perform just fine. But the answer changes depending on the component.
Structural and Safety Components
Frame components, crumple zones, and structural reinforcements are engineered to absorb and redirect crash energy in a specific way. OEM parts are tested as part of the vehicle's overall safety system. A structural component that doesn't meet OEM tolerances could affect how your car performs in a future collision — and that's not a trade-off worth making to save on a claim.
Sensors and Electronics
Modern vehicles rely on ADAS (Advanced Driver Assistance Systems) — lane departure warnings, automatic braking, blind-spot monitoring. Many of these systems depend on sensors built into bumpers, mirrors, and windshields. Aftermarket parts in these areas may not calibrate correctly with your vehicle's systems, which can trigger warning lights, cause malfunctions, or worse, leave a system that appears to work but doesn't respond accurately when it counts.
Body Panels and Trim
This is where aftermarket parts have the most acceptable track record, particularly when they're CAPA-certified. Fitment is still worth scrutinizing, but the risk is considerably lower than with structural or electronic components.
Your Rights in California
California law gives you the right to choose your own repair shop regardless of what your insurer recommends. You also have the right to request OEM parts, though your insurer isn't always required to cover the cost difference when aftermarket alternatives exist.
If an insurer specifies aftermarket parts and you want OEM, you can negotiate — and you can ask your shop to advocate for you during the claims process. That's something we do regularly for customers in Fullerton, Anaheim, Placentia, Brea, and La Habra. Knowing your rights before the repair starts puts you in a much stronger position.
How to Know What Parts Are Going Into Your Vehicle
Ask for a written estimate that itemizes every part. Look for notations like "A/M" (aftermarket), "OEM," or "LKQ" next to each line item. If the estimate lists aftermarket parts for structural or safety-related components, ask why — and whether OEM is available.
A shop working in your interest will explain the reasoning and give you options. A shop working to satisfy an insurer's cost targets may not volunteer that conversation.
Our I-CAR certified technicians at Emfix Collision walk through repair estimates with customers and explain exactly what parts we plan to use and why. We use Car-O-Liner equipment for frame straightening and refinish with Cromax waterborne and Valspar solvent paint systems. The quality of a repair depends on the quality of every component involved, and we don't cut corners on that.
Which Should You Choose?
There's no single answer that fits every repair, but here's a practical framework:
| Situation | Recommendation |
|---|---|
| Structural or frame repair | OEM strongly preferred |
| ADAS sensors or camera housings | OEM strongly preferred |
| Older vehicle, cosmetic panel | CAPA-certified aftermarket may be acceptable |
| Newer vehicle under warranty | OEM to protect warranty coverage |
| Luxury or specialty vehicle | OEM to maintain value and fit |
If your insurer is pushing back on OEM parts for a newer vehicle or a safety-related component, that's worth pushing back on. California law and your policy terms may give you more room than you think — and a shop that isn't beholden to your insurer can help you make that case.
If you have questions about an upcoming repair or want to understand what your estimate actually says, call or text us at 714-872-4442 or reach out through the contact form at EmfixCollision.com.
Frequently Asked Questions
What does OEM mean in collision repair?
OEM stands for Original Equipment Manufacturer. OEM parts are made by or to the exact specification of the company that built your vehicle, designed to fit and perform the same way as the original components.
Are aftermarket parts safe to use in collision repairs?
It depends on the part and whether it's certified. CAPA-certified aftermarket parts for cosmetic panels on older vehicles can be a reasonable choice. For structural components, safety systems, or ADAS sensors, aftermarket parts carry more risk and OEM is generally the better option.
Can my insurance company force me to use aftermarket parts?
In California, insurers must disclose when non-OEM parts appear in an estimate, but they aren't always required to pay for OEM parts when aftermarket alternatives exist. You have the right to request OEM parts and to negotiate. Working with an independent shop that isn't in a direct repair program gives you a stronger advocate in that conversation.
What is a CAPA-certified part?
CAPA stands for Certified Automotive Parts Association. CAPA certification means an aftermarket part has been independently tested and verified to meet OEM-equivalent standards for fit, finish, and material quality. Not all aftermarket parts carry this certification, and it matters when evaluating what's going into your vehicle.
What is an LKQ part?
LKQ stands for Like Kind and Quality. These are used OEM parts sourced from salvage vehicles — original manufacturer parts, but with prior wear. They can work for certain repairs, though they're generally not ideal for high-mileage or safety-critical components.
Does using aftermarket parts affect my vehicle's warranty?
It can. If your vehicle is still under a manufacturer's warranty, non-OEM parts used in a repair may affect coverage for related systems. Review your warranty terms and ask your shop before approving an estimate that includes aftermarket parts.
How do I know what parts are being used in my repair?
Ask for a written, itemized estimate before work begins. Look for notations like "A/M" for aftermarket, "OEM" for original equipment, or "LKQ" for used parts next to each line item. A reputable shop will walk you through the parts list and give you the option to request OEM where it matters most.
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