The differences between OE OEM and OES parts
OE – Original Equipment – This part is made by the car manufacturer or an auto parts supplier and is marked with the car manufacturer’s logo and/or on the car manufacturer’s box.
OEM Original Equipment Manufacturing
OES Original Equipment Supplier
Auto manufacturers do not make all the parts that they put on their vehicles during assembly or repair, they contract with auto parts manufacturers to make parts for them. For the most part, the automaker makes the body, frame, and major engine components; the rest are ‘contracted’ to OEM/OES manufacturers. The auto manufacturer provides the specifications to the OEM/OES manufacturers for the parts they need. The OEM/OES builds the part to these specifications, adds a logo, and ships it to the automaker.
Bosch, Bilstien, Boge, Beru, Mann, ATE, to name a few, are all OEM or OES suppliers to car manufacturers. They make parts from spark plugs to exhaust parts. The difference between OE and OEM/OES is mainly that OEM/OES usually do not have the logo of the car manufacturer, but they are exactly the same part. Sometimes the logo is removed from the part by the OEM/OES company so as not to affect the contract with the car manufacturer. The same part that comes off the same assembly line as the OE part.
OEM/OES parts are less expensive because they don’t go through the car manufacturer’s parts system. Every time an OE part goes through a depot, warehouse, or dealer, a little more money is added to the cost of the part. This is the main reason original equipment parts cost more. OEM/OES do not go through this procedure, our buyers get them directly from the manufacturers, keeping prices low.
Aftermarket: Aftermarket parts are just that, aftermarket. They are not made by car manufacturers. They may be made by one of the original equipment manufacturing companies or by a completely different manufacturer. The main difference is that they are not completely built to the car’s build specifications. This is not always bad. An example is Bilstien. They are an OEM/OES supplier, but offer aftermarket parts as well. There are HD struts/shocks that are original equipment, but their sport struts/shocks and suspension kits are not made to OE specs, better but not OE, so it is now an aftermarket part. Another example is the Stewart EMP BMW water pumps. Stewart EMP is NOT an OEM/OES manufacturer, but the pump they make is better and stronger than the OE. It’s an aftermarket part, but an overall better part.
But yet another example of a BAD aftermarket part is a counterfeit part. Counterfeit part manufacturers use reverse engineering to obtain the specifications of the part without paying the car manufacturer. And almost all the time these parts are made with very low quality components. Sometimes these pieces are very difficult to identify because a lot of emphasis is placed on the appearance of the piece and not on the material from which it is made. One way to identify a counterfeit piece is its incredibly low price, the old adage that you get what you pay for fits here. The best way to avoid these cheap, low-quality parts is to buy your parts from a reputable source, one that offers a warranty and return policy.
Almost all performance parts are aftermarket parts, again, be careful with these parts as well. Buy from a reputable supplier or manufacturer.