The world of auto parts has its own little thing going on when it comes to classifying parts into different categories. There are OEM parts, Genuine, aftermarket, but also OES parts.

If you’re not familiar with these designations, there’s a decent chance you’re at least a bit confused. No worries, though. We’re about to lay it all out for you and hopefully clear up any questions you might have had about this subject.

In the Beginning, There were Genuine Parts

To fully grasp how auto parts are categorized, we need to go all the way back to the beginning of the cycle. For the purposes of this article, we’ll say that it’s 1996 and BMW has just released a new 3-series — the majestic E46. The new model has all the trademarks of a great driver’s car, and the market is responding well to its release.

BMW has already built a certain number of these new 3-series cars, while any future orders will be taken care of by the new production line that’s been built within BMW’s existing network. Parallel to this new vehicle production line, BMW has set up the production of spare parts for the new car.

Here’s the thing — It’s not feasible for BMW to build an entire manufacturing network for spare parts alone. Instead, they reach out to 3rd party manufacturers whose sole purpose is to crank out spares for various car brands, using said car brands’ specifications.

The parts built per BMW’s contract have to meet specific standards of quality. In fact, we can assume that BMW is in full control of the quality control side of the process. These are known as Genuine parts.

OEM and OES Vehicle Parts — What’s the Difference?

When you shop for auto parts, you’ll run into terms OEM and/or OES during your search. OEM and OES are essentially synonymous. OES stands for Original Equipment Supplier while OEM stands for Original Equipment Manufacturer.

Here at eEuroparts.com, we label our OES parts as OEM because they are essentially the same. With that piece of information out of the way, let’s get back to our new 3-series.

As a part of the contract between BMW and the 3rd party manufacturer, BMW has allowed their partner to make their own line of spares for the new 3-series. However, these spares don’t bear BMW’s branding. Instead, they feature the markings of the company that made them. Such parts are known as OEM or OES spares.

The next time when you shop for parts and run into OEM products, you’ll know that those were made by the same factory that makes Genuine parts for your vehicle.

The Difference in Quality Between OEM Parts and Genuine Parts

So if both Genuine and OEM/OES parts are made in the same factory, that means they’re about the same in quality, right? Actually, yes. That’s one of the most interesting facts about the auto parts industry — OEM and Genuine spares are almost indistinguishable in quality.

But wait, if these two types of parts are of the same quality, how come Genuine parts cost more? The difference in the price between the two has very little to do with quality. Instead, it has to do with warranties that come with each type of spare.

Most Genuine parts come with an extensive warranty. The car manufacturer, in our example BMW, is confident that Genuine parts are built to spec and will guarantee their performance. When you cross to the OEM side, you’re also getting certain warranties, but the OE manufacturer isn’t willing to go as far as the car manufacturer. Hence, lower prices.

It all works out in the end. When you shop for OEM, you’re getting more value for your money. Of course, if you want that extended warranty that’s granted by the Genuine part, you can search for a decent deal on that side of the aisle. It all comes down to what you want to do.

Aftermarket Parts – The Redheaded Stepchild of the Auto Parts Industry

Alright, we know what Genuine and what OEM/OES parts are. What about the aftermarket segment?

The aftermarket segment is where things get interesting. These parts are completely unregulated in terms of quality control, performance and durability.

You can find super cheap spare parts of questionable quality or over-engineered products that cost a lot but sometimes solve an issue that an OEM contractor simply couldn’t be bothered with. Yes, there are actual instances of aftermarket picking up the slack and giving customers a better solution than what both OEM and car manufacturers came up with.

Naturally, you have to be careful with the aftermarket segment. Cheap is rarely good, but there are definitely many quality parts and brands in here. All you need to do is search for the right stuff and vet your picks properly.

Specialized Aftermarket

One last thing worth mentioning regarding the aftermarket segment is that certain brands like Bosch specialize in building a range of various components. So if you’re looking for a fuel pump for your new E46, the one Bosch offers as aftermarket could very well be better than the OEM, simply because Bosch has decades of experience under its belt.

Shop for OES/OEM Parts for Your Vehicle

If you’re searching for OEM parts, Genuine, or aftermarket parts for your European vehicle, you’re in the right place! We offer one of the largest catalogs of spare parts for European cars in the United States. To find the spares you need, simply input your vehicle’s data into our search bar, and you’ll be presented with a list of parts that match your inquiry.

When you select each part, you’ll easily see whether it’s an OEM, Genuine, or aftermarket by checking the Quality rating usually located above the Add to Cart button.

If you have any questions regarding our offer, or any part, in particular, feel free to contact our customer support. We’re standing by to help!