There are many categories of aftertreatment parts, and we are going to focus on DPFs, Clamps, Gaskets, Sensors, and DOCs but the same principles also apply to other components such as SCRs and EGRs. 

All DPFs and DOCs sold in North America must be self-certified with EPA. If the EPA receives complaints, the product line can be fined.  Most OEM units have North American made substrates and substrate quality is important for proper flow and capturing ash.  At REP we go an extra step. Before we package our HD DPFs, we weigh and flow test each and every individual unit, then the weight in grams is stamped on the ID tag and flow information is available by serial number. 

One warning sign a DPF is low-quality?

If the price is too good to be true, understand the source of the product, it may not be up to the OEM standards for both flow and performance.

OEM clamps are built to high tolerances to grab and squeeze two flanges with a gasket in between. Most REP clamps are sourced from the same manufacturer supplying the OEMs. These clamps are built to the same specs the OEMs use. It is also important to replace clamps and gaskets when servicing these systems. Clamps are built to very tight tolerances and over time with countless hot/cool events, road vibration, and the stress of the weight of the system, the clamps become stretched and can lose the ability to squeeze the gasket correctly.

What are the warning signs a clamp is low-quality?

If you see a general-purpose clamp, one that fits many applications, beware. Emission systems are built to high tolerances and the clamps are designed to keep exhaust gases and heat in the system so it can perform optimally.

Gaskets are made of various materials to seal the system over the long run. REP uses the same or better materials in our Gaskets as the OEMs. This is important if you want your replacements to perform. Saving a few cents on a gasket can cost someone a missed delivery or a tow bill.

What are some warning signs it is low-quality?

If the price is too good to be true, it can end up costing big time! Materials that appear very different from the OEM product are also a warning sign. Thickness is also very important; if a clamp seems too loose, it could be a gasket issue. We can’t stress enough the importance of using quality parts in these emission systems. The systems are built to deliver the heat and exhaust pressure to the emissions system to ensure proper performance.

Sensors are an integral part of the emission system; they tell the engine what is happening, and the engine reacts to that information. Replacement sensors should fit and respond the same as the original unit. Each year REP spends countless hours and money testing our sensor line to ensure that when it is installed it will perform the same as the OEM, if not better.

What are warning signs it is low-quality?

At every trade show we attend we are approached by numerous suppliers vying for our business. Many of the sensors presented to us may look similar to the OEM part, but the wiring is thinner, and the plugs may be of inferior quality. Then there is the programing, it needs to react the same as the OEM.

The DOC is the heart of the system, and this is often where the majority of the catalyst resides, so make certain you are buying from a reputable source. Again, these systems are designed to work as a system and each replacement part must work in harmony with the other components. If one over or underperforms, it can throw off the entire system. At REP we do our best to source substrates from the same source as the OEMs. We offer catalysts that perform the same as the OEM to make certain the system performs as designed.

What are the warning signs it is low-quality?

Again, we can look at the price. If a price is too good to be true, someone is sacrificing somewhere. Look for an exact fit, quality welds, and straight flanges.