Why would you need to replace the factory plenum on your 6.7L Cummins? Well, there's a few reasons. Number one, this is where your grid heater is housed, and if your grid heater failed, this is how you would replace it. Secondly, the grid heater has been known to accumulate soot as part of the EGR process, causing a major blockage. And lastly, possibly you replaced your stock plenum with an aftermarket unit that does not feature the grid heater and you are ready to reinstall it. No matter the reasoning, we offer this genuine OEM direct replacement for an easy install.