OEM OES And Aftermarket Auto Parts And Their Pros And Cons

You’re quoted a price for a car part. So, you go online to see if the quote is a fair one. Just, for example, you type “auto parts for cars phoenix az” into a search engine. You come across the terms OEM OES and aftermarket parts. Now you are wondering, “What is the difference between the two and is better than the others?” 

OES OEM And Aftermarket Defined 

Original Equipment Supplier (OES) and Original Equipment Manufacturer (OEM) is almost two ways of expressing the same thing. In order to become an OES part, some of the OEM parts will be stamped with the auto manufacturer’s logo and part number. OES parts are installed by car builders on the assembly line. OEM replacement parts are used and sold by auto dealerships. Aftermarket parts are used by private repair shops and do-it-yourselfers and sold through independent auto parts stores. 


OEM parts are made to the specifications of auto producers. This means that once installed an OEM part will fit a car exactly as it should. There is a natural assumption that OES and OEM are better than aftermarket replacement parts. This assumption is partially true. 

The quality of aftermarket parts will depend on the manufacturer. While aftermarket parts are less likely to fit your car as perfectly as an OEM part, some websites point out that some aftermarket parts exceed original equipment manufacturer parts in quality. Aftermarket parts are for those whose main concern is price. OEM parts come with a warranty. Aftermarket parts may not be covered against defects. 


Aftermarket auto body parts on average are 60% cheaper than OEM. This is why auto insurance companies gravitate towards aftermarket parts. More about that later. 

With multiple producers, there is a greater selection of aftermarket parts which can be a double-edged sword. More producers mean more competition which creates more opportunities to save on aftermarket parts. On the other hand, greater selection means a greater risk of choosing a poor quality part. OEM parts are more expensive than aftermarket parts because they are theoretically of a higher quality than their aftermarket counterparts. Also contributing to the higher cost is the multiple middlemen involved in getting the part from factory to dealership. 

Aftermarket Parts and Insurance 

I mentioned earlier that auto insurance companies prefer aftermarket parts to original equipment manufacturer parts. Many auto insurance companies will only cover the cost of aftermarket parts. If you insist on OEM parts your insurer will want you to pay the difference in cost between your preference and aftermarket parts. Normally, using aftermarket mechanical parts doesn’t affect the cars resale value. 

When it comes to bodywork some websites warn that you should insist on OEM parts. Earlier it was mentioned that some aftermarket parts don’t conform perfectly to factory specs. Fenders, doors, hoods etc. that don’t fit right can hurt your resell value. An ill fitting hood that doesn’t close properly can be dangerous.

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