Are the OEM Diesel Engine Rebuild Kits Worth It?

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Are you able to tell the difference between run-of-the-mill aftermarket parts and quality aftermarket parts? Sometimes it’s hard to discern the difference.

A part is “aftermarket” if it was made by a company that didn’t make the original parts or engine. OEM (Original Engine Manufacturer) refers to the company that originally made and/or sold an engine. Examples of major OEMs in the heavy-duty diesel world would be Caterpillar, Cummins, Detroit Diesel, etc.

You’d probably assume OEMs supply the “right” parts for your engine, and they’re the only source for quality parts. Aftermarket parts then get a bad reputation: they’re junk, they don’t hold up, or they won’t fit properly. There’s no denying that OEM parts will work, but are they really the only good option for your engine?

OEM Engine Rebuild Kits

Advantages of Buying an OEM Rebuild Kit

Buying OEM diesel engine rebuild kits has some advantages. The biggest advantage is that these kits contain the same parts your engine was built with, so you know they’re good quality. You also know they’ll fit correctly. This peace of mind is the main reason people buy OEM parts when fixing their engines.

OEM parts typically come with a warranty. Most OEMs will provide 6-12 month warranties: a decent length of time that satisfies most people.

OEM parts are usually readily available, especially if they’re parts for a newer engine model. If you have a brand-new engine, then OEM might be the only option.

Disadvantages of Buying an OEM Rebuild Kit

The biggest disadvantage of using OEM diesel engine rebuild kits? They’re expensive. When you buy big brand products, they’re almost always more expensive than aftermarket or generic alternatives. The diesel industry is no exception. If an OEM logo on the box is important to you, you’ll definitely pay a premium.

And while OEMs have the best availability for brand new parts, their availability for older engine parts is spotty at best. The older an engine is, the less likely OEMs will carry parts for it.

Another big downside to genuine parts is that many buyers don’t realize what they’re getting when they purchase OEM. For example, Caterpillar cylinder kits come pre-assembled to save time. What they leave out, though, is that the pistons in the cylinder kit may be used. It’s common practice for Caterpillar to add used pistons to cylinder kits. You wouldn’t be able to tell from the price that only half of the cylinder kit is brand-new parts.

Aftermarket Engine Rebuild Kits

Are Engine Rebuilds Worth it? Advantages of Buying an Aftermarket Rebuild Kit

One of the biggest advantages of buying diesel engine aftermarket kits is that they’re almost always more affordable than genuine kits. It’s well-established that aftermarket parts are cheaper regardless of what part you’re buying. If you’re a repair shop, the importance of pricing matters even more. Price is important, but there are other upsides to buying aftermarket parts.

Sometimes aftermarket parts will give you the same parts your engine came with. Yes, you read that right. Sometimes, if you buy from the right seller, you’ll get original engine parts. OEMs might manufacture the entire engine, but the parts that go into an engine aren’t always OEM. If you pick up an OEM diesel engine rebuild kit, many of the components will come from independent manufacturers. One of these manufacturers is Mahle, which supplies pistons and piston rings to several OEMs. The thing is –Mahle also supplies pistons and piston rings to several aftermarket companies. So if you’re buying from one of these aftermarket companies Mahle supplies too, you’re getting the exact same piston/piston rings you’d get from the OEM, but without a logo –and at a greatly reduced price. (PS: HHP is one of those aftermarket companies.)

Some manufacturers exclusively make aftermarket parts. This can also be a good thing. Many aftermarket manufacturers make parts that are just as good as OEM parts. Some aftermarket manufacturers make parts even better than the originals by improving the part’s design. These companies take time to study OEM parts, learn their flaws, and discover how to fix them. They give you a better quality part for less.

Despite many aftermarket manufacturers providing parts of equal or better quality to OEM, aftermarket parts have received a bad reputation. To dispel these concerns, the aftermarket manufacturers find ways to prove the quality of their products. One way they provide is by offering double the warranty of the OEM. Most OEM warranties last 6-12 months; not bad, but wouldn’t you want a 12-24 month warranty from an aftermarket manufacturer instead?

Aftermarket companies will only sell you diesel engine rebuild kits with all-new parts. They won’t hide used pistons in their cylinder packs, they’ll sell you new ones instead. If you want used pistons, you can just buy a re-ring kit and use your own.

Aftermarket manufacturers also have older engine parts more readily available than OEMs. If an OEM no longer carries a part for your truck or tractor, there’s a good chance an aftermarket company will have it.

Disadvantages of Buying an Aftermarket Rebuild Kit

Unfortunately, there are disadvantages to buying aftermarket diesel engine rebuild kits.

When buying aftermarket, don’t just buy any aftermarket rebuild kit. Not all manufacturers are alike, and they won’t always have the advantages listed above. You need to be very particular about your parts supplier. At HHP, we actually bought cheap parts advertised from another aftermarket seller and tested them ourselves. We pitted them against similar parts from another aftermarket manufacturer we trust. This was the Ultimate Battle of the Parts.

Those cheap parts whose price seemed too good to be true? It was. That’s why HHP only sells parts from known and trusted manufacturers. HHP has been in the business long enough to understand a manufacturer’s failure rates, their strengths, and whether or not to avoid certain parts from them. For example, some manufacturers make great gaskets, but not great pistons. So we know to get gaskets from them and pistons from another, more reliable manufacturer.

Another sad truth? Aftermarket parts on newly-designed engines aren’t as readily available from these manufacturers. Aftermarket manufacturers cannot design a part that has a patent on it. It also takes a while to perfect a design, especially if it can’t be worked on immediately. Instead of rushing the engineering process to get parts available faster, a good aftermarket manufacturer takes time to design its parts correctly. This might mean you’ll have to wait a few years to get aftermarket parts for a brand new engine.

Conclusion

You can’t deny the quality of OEM parts; these brand names are big for a reason. However, if you don’t want to be overcharged for a part –and you have a good supplier– the aftermarket is the way to go. You can get an aftermarket part for the same or better quality, with twice the warranty, and at a fraction of what OEM would charge you. Again, we cannot stress how important it is to buy from the right supplier! A quality parts supplier will find the best parts and steer you away from the cheap manufacturers who gave aftermarket parts their bad reputation in the first place.

Want to know more about our aftermarket rebuild kits, or get quality parts at a lower price? Call Highway and Heavy Parts at 833.990.3406 or request a quote online today!