Face Plugging the DOC Filter

Essential Takeaways

  • Face plugging hinders the performance of the DPF & SCR downstream
  • A face plugged DOC filter will cost you quite a bit, so preventing this from occurring in the first place is essential.
  • Performing forced DPF regenerations regularly will burn the soot out of your DPF and it will create ideal conditions for cleaning the face of the DOC filter.

What is face plugging? How does it happen? How can you fix it? What can you do to prevent it? In this blog post we will be answering these commonly asked questions!

What is Face Plugging & How does it happen?

Face plugging is an extreme buildup of carbon on the inlet side of your DOC (Diesel Oxidation Catalyst). This extreme buildup causes additional exhaust backpressure and restricts exhaust flow, which hinders the performance of the DPF and SCR downstream. While the face plugging can be caused by a few different mechanical problems, the most common is how the truck gets used. Low exhaust temperatures, typically caused by trucks or equipment that spend most of their time in idle or low engine workloads, are extremely vulnerable to this condition and are at most risk.

How Can You Fix a Face Plug?

When you do find yourself with a DOC filter that has been face plugged there are a few ways to get it cleared up, although none of them are cheap. A cleaning procedure that some of the OEMS have available from through their dealer network does exist. The repair times range, but the procedures typically have a minimum charge of 5 hours of labor. You could also remove DOC filter and have it baked. And if your DOC filter can’t be cleaned you need to replace it entirely. None of these scenarios sounds fun and will leave your wallet a bit lighter.  

Prevention: The Solution to Your Problems  

For trucks that live their life idling and driving with light loads, or from traffic light to traffic light, I would recommend getting a maintenance schedule going before face plugging becomes a problem.

If you are in an area where you can really work out the engine by doing sustained higher load hill climbs or spending some time over the road with it, that will do wonders for building exhaust temperatures and getting it cleaned out.

Another option would be to utilize the OTR diagnostics before you have a problem.

Creating Your Forced Regeneration Schedule

OTR diagnostics tool will allow you to do forced regenerations on your schedule. Forced regenerations kill two birds with one stone. The regeneration process builds up temperatures in your exhaust and it creates increased engine load for burning the soot out of your DPF. As a byproduct, it also creates great conditions for cleaning the face of the DOC. Creating a schedule to perform forced regenerations every few weeks it goes a long way to prevent many aftertreatment issues.  

Pay attention to your truck!

The last thing I cannot stress enough is to not ignore your truck. The MIL indicators are still an early warning system, and in some cases not early enough. Attending to the issues as quickly as possible will help prevent damage that carries a much larger cost.

Until next time! 👋
Stay safe, stay healthy & be blessed.