OEM Ford parts are automobile parts that are made by the original equipment manufacturer as the parts that originally came on the car, or parts that another company has been licensed to make.  In the latter case the parts must be made exactly to the original parts’ specifications, making them the same quality as the original manufacturer’s parts, and therefore deserving of the title of OEM Ford parts.

Aftermarket parts, on the other hand, have no such regulations governing them.  They do not have to be the same quality as the original parts on the car, and often are decidedly not.  Many aftermarket parts manufacturers make parts that can fit on several different makes and models, which streamlines the manufacturing process. On the other hand, it can make repairs difficult for mechanics and do it yourselfers who find an aftermarket part doesn’t fit the way it should.

As you can probably imagine, OEM Ford parts are better than their aftermarket counterparts, for several reasons:

They are better quality than aftermarket.  As already explained, OEM Ford parts are either the same exact parts as originally on your car when it was sold, or made to the same specifications as the original parts.  Since aftermarket parts do not have to stick to these quality standards, OEM parts are usually much better quality.

They last longer than aftermarket parts.  Nearly everyone has had the following type of experience: When their car is perhaps 15 years old and has 130,000 miles on it, one of the original parts goes out and needs to be replaced.  Because the aftermarket part is cheaper and perhaps has a better warranty, that is what the owner chooses.  A year or two and no more than 20,000 miles later, the part fails again.

What happened?  Well, because aftermarket parts do not have to adhere to the same standards as OEM, they are not made well, and therefore do not last as long as the parts originally installed on the car. Manufactures will change the part to fit multiple models to reduce costs, but oftentimes the parts don't wear well because they don't fit precisely. The only way to get the same life out of a replacement part is to buy OEM.

They offer better value for your money.  Many do it yourselfers are sidetracked by the fact that aftermarket parts are so much cheaper than OEM parts.  Furthermore, many aftermarket parts stores offer lifetime warranties with their parts, while the dealership usually only offers a year warranty with OEM parts.  This is not really because the aftermarket parts are expected to outlast the OEM parts.  In fact, it is just the opposite: An aftermarket part lasts for a fraction of the life of an OEM part.

By offering extended warranties, aftermarket parts stores are gambling that a larger percentage of buyers will not take advantage of the warranty, which is their competitive advantage and drives the sale.  Since the warranty is non transferable, it is voided if the owner sells the car, which most do.  Also, they are betting on people not keeping their receipts or remembering where they got the part in the first place.

It is important not to forget the time and effort it takes to replace a part.  If time is money, then you may not be saving any money by purchasing the cheaper part, even if it does come with a lifetime warranty. Cost is an important consideration, even for all but the most fortunate of people; it is worth spending extra for the quality, longevity, and value of OEM Ford parts.