OE, OEM, Genuine and Aftermarket Parts Terminology Explained

It can be confusing when ordering parts to see different acronyms. What does OE and OEM mean? What is the difference between genuine parts and aftermarket parts?

OE is short for Original Equipment, which means the part is the same as would be supplied by the main dealer but would be presented in a different packaging and have a different part number. So an OE part would be identical in every way, made by the same manufacturer using the same parts and materials as a genuine part, but is often cheaper because it would have the manufacturer's packaging instead of the car manufacturer's packaging.

OEM is short for Original Equipment Manufacturer, which means the part was manufactured by a reputable manufacturer who also supplies components to the car manufacturer, but not necessarily this exact part. You can be assured that OEM parts are of the highest quality.

GENUINE PARTS are supplied by the car manufacturer and will be branded in some way, either by a logo, branded packaging or part number. Genuine Parts are what the car manufacturer fits when building new cars and would supply from their parts counter as replacement parts. However, only a few car manufacturers manufacture all their parts themselves. Car manufacturers are assembly plants that assemble many parts from many suppliers to make cars. You will often find some parts fit many different makes and models. For example, brake pads and oil filters may fit many different makes and models, so these are often sold as OEM parts, see above.

AFTERMARKET PARTS are parts manufactured by manufacturers that don't meet any of the above criteria. These parts can also be referred to as 'pattern' parts, i.e., copies of the original. Aftermarket parts used to have a bad reputation; they used to be very cheap, and often, they did not fit properly, and the quality was not very good. Things have improved over the last 5 years and aftermarket parts are much better than they used to be. Buying aftermarket parts is fine. Look out for recognised brand names and buy from established, reputable companies offering at least a 12-month warranty.