The Wide World of Automotive Parts: Genuine, OEM/OE/OES, Aftermarket, and Understanding The Differences

The Wide World of Automotive Parts: Genuine, OEM/OE/OES, Aftermarket, and Understanding The Differences

European vehicles are renowned for their meticulous engineering, with each component of brands like BMW, Mercedes, Audi, and Porsche undergoing numerous revisions to achieve perfection. This is evident in everything from the interior design to the suspension and drivetrain. Consequently, these cars often come with higher price tags than their Asian or American counterparts, reflecting the quality and craftsmanship invested in them.

The downside of this precision engineering is the cost of replacement parts. These parts are expensive due to the same high standards applied to the vehicle’s initial construction. However, there is a cost-effective alternative: purchasing OE (Original Equipment), OEM (Original Equipment Manufacturer), and OES (Original Equipment Supplier) parts.

The Common Misconception About Automotive Parts

A common misconception is that the Manufactured brand makes all parts of your vehicle. This is far from the truth, and this is not a bad thing. The sheer magnitude of parts required for each vehicle would be nearly impossible and inefficient to produce entirely in-house. Every car on the road is the result of a collaboration between countless brands to make your beautiful Frankenstein refined and without all the stitches. 

So, when it comes to the inevitable moment a part ends its life cycle and it is time for replacement, the available options can be summed up in 3 main categories: Genuine, OE/OEM/OES, and Aftermarket. Let’s explore all three and shed some light on the differences.

Starting with the “Genuine” article

When rolling off the factory line, genuine automotive parts are those branded by the manufacturer. These parts will either be an exact match to the part in your car when it rolled off the factory line or an exact match to the part that supersedes the original (an updated or improved version of the original). In almost all cases, these parts are made by a separate parts company from the vehicle manufacturer but branded as the vehicle make (ie, Mercedes, BMW, Audi, etc.). For example, Textar Brake Technology makes some of the brake pads for Audi, but when buying genuine pads, the brake pads will be branded and sold as Genuine Audi pads.

Understanding OE, OEM, and OES: Still the Real-Macoy

“OE” stands for Original Equipment, which refers to parts made by the same companies that supply automakers, like ZF or Lemfoerder. These parts are identical to the “Genuine” parts you’d find at a dealership but are sold under the part manufacturer’s brand rather than the vehicle’s brand. “OEM” parts are similar but are made by companies that didn’t initially supply the parts for a specific model yet produce parts for the vehicle manufacturer. For example, if Bosch supplies ignition coils to BMW, they are OE, while NGK, which also makes compatible ignition coils, would be considered OEM. The part numbers will align, and fitment and quality will be comparable to the “genuine” part. 

Let’s expand a little further still on these terms:

What is OEM?

OEM stands for Original Equipment Manufacturer. This term refers to companies that produce parts and equipment that may be marketed by another manufacturer. In the context of the automotive industry, an OEM is the original producer of a vehicle’s components, and they are often associated with manufacturing parts for more than one automaker.

For example, if Bosch made the parts for some of the brake systems for a car, then Bosch would be the OEM in the case of those specific parts. OEM parts are precisely those that were used in assembling the vehicle. They match the ones that come with your vehicle when it rolls off the production line.

What is OE?

OE or Original Equipment refers to the parts and components used in the original production of the vehicle. Essentially, OE and OEM mean the same thing. An OE part is an original part used in the car’s original manufacturing process.

For example, if you buy an OE brake pad, you’re purchasing a part that was likely made by the same supplier that made your vehicle’s brake pads when it was new.

What is OES?

OES stands for Original Equipment Supplier. This term also refers to the company originally producing the part for the vehicle manufacturer. It is essentially the same as an OEM. However, the difference lies in the context in which these terms are used.

OES is typically used when a part is directly sourced from the manufacturer of the original part, while OEM parts could be sold through a variety of channels, including the aftermarket. For example, if you purchase a Bosch brake pad directly from Bosch, it’s an OES part. If you buy the same pad from a third-party retailer, it’s an OEM part.

So, what matters?

The key difference between these terms is their usage and context rather than their meanings.

In the world of automotive parts, the three acronyms are often tossed around interchangeably. Ultimately, for argument’s sake, these terms carry the same weight regarding quality. The only difference is the lighter impact on your wallet compared to the “Genuine” parts.

The main benefits of OE/OEM/OES parts are cost-effectiveness and availability. They are sold directly by the part manufacturers, eliminating the markup added by vehicle brands. With global supply chain issues affecting availability, OEM parts are more readily available than genuine parts, as they don’t have the same supply obligations to automakers.

Aftermarket and Performance Parts

Apart from OE/OEM/OES, there are also Aftermarket and Performance parts. These are not made by original suppliers and often vary in design for performance enhancement or cost reduction. The quality of Aftermarket parts can vary greatly, but reputable suppliers ensure high-quality products. Performance parts offered by companies like Ohlins and Bilstein are designed to enhance vehicle performance beyond standard specifications. 

Alternatively, lower-cost options that serve the same purpose are available. Remember, while not always the case, prices typically reflect quality. So, be mindful of the application and consult with your local expert if you have questions. As a general rule of thumb, we recommend buying the best you can afford when equipping your vehicle with the appropriate parts for the job.

A Word on Phoney Baloney: How To Spot Counterfeit Car Parts

Unfortunately, counterfeit products are a real problem regarding automotive parts. These fake parts don’t meet industry safety and quality standards and can lead to breakdowns, engine failures, and even accidents. Here’s how to spot them and what to avoid:

Check the Packaging: Authentic parts come in high-quality branded packaging, while fake ones are usually packed in cheap, flimsy materials without proper labeling. Look closely at details like print quality, box material, and thickness.

Only Purchase From a Reputable Source, and Consider the Price: While we all love a good deal, an extremely low price can be a warning sign of a counterfeit part. Genuine parts are typically more expensive due to their superior quality and come with a warranty. So always ask about warranty details when buying a car part. And remember, like most things, it’s usually too cheap for a reason. 

Look for Serial Numbers or Holograms: Genuine OEM parts have specific serial numbers or holograms that can be traced back to the original manufacturer. These might be printed directly on the box or part, while counterfeits often use stickers.

Watch Out for Typos: Typos on the packaging or instructions can be a giveaway. Inspect the part more closely if you spot typos, grammatical errors, or misspellings.

Read the Instructions: Counterfeit spare parts often come with incomplete or confusing instruction manuals. Be wary of missing steps, diagrams, or unclear sentences.

Compare Old and New Parts: Look for differences in colour, weight, dimensions, and more when you compare your new part to the old one. Even a minor difference, like mismatched fasteners, could indicate a counterfeit replacement part.


In summary, Genuine parts assure optimal quality and fitment. While OE/OEM/OES parts offer a cost-effective and reliable alternative without compromising quality. They are often identical to genuine parts, the primary difference being the absence of the vehicle manufacturer’s branding. 

At Haus of Cars, we work with you to provide a comprehensive suite of options and help you choose the best option to fit your needs and budget. Contact us today for more information

Select your currency
USD United States (US) dollar