The term OEM can refer to many industries, however, I believe we hear that term mostly in the automotive industry. While we look for an oem parts definition as it relates to auto parts, we need to keep in mind that some places use it loosely. The official abbreviation stands for “original equipment manufacture“. Pertaining to automotive parts, mechanical or body related parts, it usually means a part made from the original company who made the vehicle, or dealer part for short. These parts are the exact same fit and finish as when the car was built, which means they “should” be a perfect replacement. Here are some other points to consider:
Genuine OEM Parts
You may see this term or possibly factory part, OEM replacement part, and OEM quality replacement part. A manufacturer often uses 3rd party companies to make parts for them. I will use a battery for this example; let’s say GM contracts out the use of AC Delco batteries in the new cars. This is a company you can go to the auto parts store and buy a battery from. It would be considered a genuine oem part in GM’s eyes but the same battery can be bought for a much better price elsewhere. It still meets the qualifications of an OEM part but is not manufactured by GM.
On the other side of the coin is what we call aftermarket parts, which is any other part made by an outside or third party company not associated with the manufacture. They will not have the exact same fit and/or function as an OEM part. Now to what degree is another story. The trade off here is cost. They can be substantially cheaper in some cases but generally a good enough savings to warrant the purchase. We need to break this down to two categories, mechanical and body.
Mechanical Aftermarket Parts
When we talk about mechanical aftermarket parts there is a much more diverse set of quality guidelines to think about. You walk into the auto parts store looking for a set of brake pads for example. Many times you probably have at least 3 choices: good, better, and best. None of which are OEM but the quality of them can be worse than OEM about the same and then even better. There are always companies who have improved upon the manufactures parts and made them better, even cheaper too. So generally there is no need to buy the dealer part. But if you are concerned with any warranty issues with your car then you would need to check with the dealer if you can put those parts on or not.
Performance parts are definitely an upgrade from a factory part. This will void any warranty you have but the parts are usually far superior to factory parts. Most car enthusiasts don’t really care about the warranty anyway so have at it. The aftermarket parts industry is huge on this end of the spectrum.
When it comes to body parts, I am referring to the sheet metal replacement panels for the factory OEM parts. If you were to mention using these parts to an auto body technician most of the responses would not be good. Most of the time these parts just don’t make the cut. Years ago they were just terrible fitting, bolt holes would not line up, lines were not even, the metal had ripples in them , etc. You would spend more time adjusting them than anything else. Fortunately, they have come a long way due to the bad press they got and loss of business. Some insurance companies have been sued over the use of these after market parts and do not use them today. However, some do and you will see a standard of quality that is fairly good in modern day. One standard is through an association called CAPA. It stands for Certified Aftermarket Parts Association. We’ll go more into that in another article.
Other Body Parts
In the same category is where you will find headlights, plastic bumpers, grilles, other lights, radiators, condensers, glass, etc. Here you will find the same holds true of the quality of the parts. Better but still not up to OEM standard in my opinion. Being in the business for years you learn what is acceptable and which parts just don’t work for a replacement part, again we’ll discuss this further in another article.