Car Parts

OEM vs. Aftermarket Parts: What’s The Difference & Which One Should You Buy

If you need to tackle some DIY maintenance or you’re interested in upgrading some of your vehicle’s components, you will come across two types of parts while shopping: original equipment manufacturer (OEM) and aftermarket. Before you start browsing and filling your virtual cart, let’s go through a few questions to better understand each type.

Difference Between OEM & Aftermarket Parts

An OEM part is made by the same company that supplies the automaker’s factory. Popular examples include ACDelco (GM), Motorcraft (Ford), and Mopar (Chrysler). Historically, you could only get OEM parts through authorized dealerships. They were the go-to for everyday consumers and purists who wanted the exact, factory-spec replacement parts for their vehicles. However, in recent years, OEM parts have become available through other retail stores and online via third-party sellers.

By contrast, an aftermarket part is a component manufactured to appear and function just like the OEM part. However, these parts are designed and produced by a company competing with the OEM supplier. They’ve always been available at brick-and-mortar auto parts stores, but aftermarket parts rose in popularity because of e-commerce retailers.

Hobbyists flocked to online stores to explore alternative replacement parts, many of which offered unique and custom variations unavailable through the original manufacturer.

OEM vs. Aftermarket Parts

Are Aftermarket Parts Less Expensive?

Although not a hard and fast rule, aftermarket parts are generally less expensive as most retailers strive to offer a competitive alternative. How much less costly, though, will depend on the type of part and its availability. It’s not unusual to see different pricing tiers for aftermarket parts based on value, so shoppers can easily browse for parts within their budget.

Pricing for aftermarket offerings will also vary depending on the retailer, with some retailers willing to offer discounts and others adding larger markups.

Are Aftermarket Parts of Lower Quality?

Years ago, when the aftermarket first started to compete with OEM suppliers, some vendors may have compromised quality to be price-competitive. This was often done to win customers who were historically loyal to OEM suppliers.

Today, much of the aftermarket realizes the importance of quality, and you can find options from many sellers that are close competitors to their OEM counterparts. In fact, some large aftermarket suppliers have made it a selling point to state that their aftermarket components are superior to OEM ones, particularly if those OEM parts have known issues.

OEM vs. Aftermarket Parts

Is There a Risk of Counterfeit Parts? 

In this day and age, sadly, there is always that risk. Think about how there are knock-off watches, sunglasses, and handbags. Auto parts, unfortunately, fall into a similar situation. Airbags, brake pads, wheels, electrical components, and various other engine and drivetrain components are among the parts most commonly at risk. Counterfeit auto parts are still on the market, despite government and industry efforts worldwide to quell the activity

How Do Spot Fake Auto Parts?

Keep an eye out for poor quality, misspellings, and wrong colors. When shopping online, look for listings that include several high-quality photos and detailed descriptions that include exact specifications. Always read through customer reviews if there are any.

One way to avoid counterfeit parts is by purchasing from reputable companies and sellers, preferably those with a dedicated customer service team available to you before and after the sale.

OEM vs. Aftermarket Parts: Which One Is Best?

In some cases, there isn’t a choice! For newer cars or for parts that are more expensive or in lower demand, OEM may be the only choice. With an OEM part, you are guaranteed an exact replacement of what was originally included on your vehicle. For some, this is incredibly important and worth any cost discrepancy or longer wait times.

On the other hand, for obsolete brands or older vehicles, OEM support may have ended, and the part you need might be hard to find. Dealers may now keep very few (if any) in stock, or the parts you need are scattered around the country, perhaps even in salvage yards. The aftermarket might provide you with the parts you need more easily in these instances.

OEM vs. Aftermarket Parts

OEM vs. Aftermarket Parts Summary

If a consumer does have a choice between OEM and aftermarket parts, the smart shopper decides after looking at brand reputation, perceived quality, warranty, and availability, in addition to price. When shopping for car parts, make sure you’ve done all your research and selected the right option that factors in budget, lifestyle, and safety. The good news is that everyday consumers and dedicated hobbyists alike have more options than ever for car parts, which can all be accessed from the comfort of your home.

Richard Reina is Automoblog’s resident expert on the classic and collector car market. He enjoys restoring and driving old cars with a special love for anything Italian. Richard is the author of The Collector Car Hobby, a free guidebook for finding and enjoying the classic car of your dreams.

  1. The topic of warranty protection when related to the “after market vs. O.E.M.” should include the The Magnuson-Moss Warranty Act. The short version and para-phrased version is something like: if a break-down or problem happens, the repair facility that attempts to void the warranty has to prove the the break-down was faulted by the after-market item. This is common with items like the engine lubricant and its filters.

  2. I like how you mentioned that parts are considered OEM because they’re manufactured in the vehicle company factory. My brother is thinking of looking for a valve timing system because he’s considering rebuilding a racing car in his garage to have as his daily driver. It seems like a good idea for my brother to think about buying auto parts from a reputable supplier so that his rebuilt car can operate as best as possible.

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