Why Does EGR Valve Get Carbon Build Up On a 6.0 (Answered!)


If you are a proud 6.0 Powerstroke owner, you might see the P0401, P0402, and P0404 codes more often than other car owners. This is why many Ford owners ask why does the EGR valve get carbon build up on the 6.0 so often.

In this blog post, I am going to talk about why does the EGR valve get carbon build up on a 6.0 and how to clean the EGR valve.

Why Does EGR Valve Get Carbon Build Up On a 6.0

Why Does EGR Valve Get Carbon Build Up On a 6.0

One of the main reasons for the EGR valve on 6.0 getting carbon buildup is due to the fact that these systems were not designed keeping in mind today’s driving conditions. Earlier, most people used their vehicles only for short distances which did not give the engine enough time to reach its optimum operating temperature. This led to incomplete combustion of the fuel which in turn resulted in soot (unburned carbon) being deposited on the EGR valve and other engine parts.

The EGR valve takes exhaust gasses that are high in nitrous oxides and sucks them back into the engine. It actually cools the combustion chamber and allows the engine to run better.

Another reason for carbon buildup on a 6.0 is the use of low-quality fuels. These fuels have a higher carbon content and do not burn completely, leaving behind a residue that gets deposited on the EGR valve.

The incorrect timing of the EGR system can also be a reason why the EGR valve gets carbon buildup. If the EGR system opens too early, before the engine has reached its optimum operating temperature, it can lead to incomplete combustion and carbon buildup. Similarly, if it opens too late after the engine has reached its maximum temperature, it can lead to overheating and damage to the engine.

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The presence of oil in the exhaust gas can also lead to carbon buildup in the EGR valve. This can happen due to two reasons; either due to an oil leak in the engine or due to incorrect valve clearance. Oil in the exhaust gas will coat the EGR valve and other engine parts, leading to carbon buildup.

How To Clean an EGR Valve on a 6.0

Why Does EGR Valve Get Carbon Build Up On a 6.0

Cleaning the EGR valve on a 6.0 or any other vehicle is much cheaper than actually replacing the EGR valve every time it gets clogged by carbon. So, each time you get a P0401, P0402, and P0404 trouble code, first clean the EGR valve and see if that fixed the issue. Here is how to clean an EGR valve on a 6.0.

1. Required tools for the task

  1. Wire brush (view on amazon.com)
  2. Liquid EGR valve cleaner (view on amazon.com)
  3. EGR valve o-ring kit (view on amazon.com)

2. Open the hood and locate the EGR valve

With the engine cooled down, open the hood and locate the EGR valve. The EGR valve on a 6.0 is located behind the air intake elbow, between the alternator and the oil filter housing. It has a round shape and is equipped with an electrical connector on top of it.

3. Remove the EGR valve

Why Does EGR Valve Get Carbon Build Up On a 6.0

First, disconnect the electrical connection and set it aside. The EGR valve is secured by two bolts which can be removed with a 5/16” and an extension. Safely store the two bolts for later. If you are clumsy like me, loosen the bolts almost to the end and then grab them with pliers. In order to remove the EGR valve, you need to pull it straight upwards. Depending on how bad the carbon build-up is, you might have to wiggle it a little bit.

4. Clean the EGR port

Why Does EGR Valve Get Carbon Build Up On a 6.0

Cleaning the port inside the actual intake where the EGR valve sits is as much important as cleaning the EGR valve itself. This is where all of the EGR flow comes from. If your EGR valve has carbon build-up, there is a great chance that the port itself has carbon build-up too.

If you leave the port dirty, all of the carbon build-ups will simply end up in the cleaned EGR valve and will cause it to fail soon.

So, grab a spatula or something that is not too pointy and scrape the walls of the port. Try to get as many deposits as you can. As you scrape them, the deposits will fall down the port, but do not worry. After you are done scraping, you will vacuum them. Make sure you get all of the deposits or else you will have a crank no start upon completion of this repair.

5. Remove the O-rings and the gasket from the EGR valve

The EGR valve has two o-rings and a gasket that seals the EGR valve to the intake manifold. It is always a good idea to remove the old ones because they are going to be dry rotted from all of the carbon. So, grab a screwdriver and remove the two o-rings and the gasket.

6. Remove the large carbon deposits from the EGR valve

The carbon build-up on the EGR valve causes it to trigger P0401, P0402, and P0404 trouble codes because it is unable to come back to the home position or get stuck and not be able to open all the way. Either way, carbon is the issue.

Make sure that you are wearing gloves because these carbon deposits will stain your hands for a week. First, start by removing any loose chalky carbon with a screwdriver. Be careful not to damage any of the components. Next, grab a wire brush and try to clean any left carbon deposits before spraying it with a carbon cleaner.

7. Soak the EGR valve into the liquid cleaner

There are a lot of EGR valve cleaners on the market. They can either be spray or liquid. I always get the liquid one because I like to soak in the EGR valve because that way it can get cleaned really well. What works for me, and will work for you too, is a kitchen measuring cup. The reason why the measuring cup is perfect is that we don’t want to soak in the EGR valve completely. There are ports that we exposed when removing the gasket which shouldn’t be sprayed or submerged as well as the electronics on top of the EGR valve.

So, fill the kitchen measuring cup with the liquid carbon cleaner and put the EGR valve in it. The little ears on the EGR valve will hold it exactly where it should and won’t allow for the ports to get wet. Leave it to soak for at least half an hour and it will dissolve all of the remaining carbon build-up.

Depending on how bad your EGR valve is clogged, you can remove it from the cleaning solution and brush it with a wire brush and then let it sit again. When done, wipe the EGR valve with a clean towel and let it dry for about thirty minutes.

8. Install the new o-rings and gasket

After the EGR valve is cleaned and completely dry, you need to install the two o-rings and one gasket. The new o-rings are made from rubber and are pretty flexible, so getting them on the EGR valve is pretty easy. The same goes for the gasket that sits on top.

9. Reinstall the cleaned EGR valve

With the new o-rings and gasket installed, it is time to reinstall the EGR valve. Place it back into the port and line up the holes so you can insert the bolts. Tighten them down evenly on both sides, little by little. The spec on the EGR valve bolts is 120-inch pounds. Then, reconnect the electrical connector and make sure it snaps all the way in.

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Hi there. I am a certified Automotive Service Excellence (ASE) mechanic since 2018 and a car detailer for 10 years.

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