If you own a 2001 - 2010 GM 2500HD, 3500HD Silverado/Sierra or TopKick/Kodiak equipped with the 6.6L V8 Duramax diesel engine, you can be sure that the fuel filter head will eventually give you some trouble and lead you down the repair rabbit hole. The reason for this issue is due to the design of the fuel filter head itself, and the omission of a lift pump in the factory design. Once this component’s seals start to fail, it will lose vacuum and cause a cascade of driveability issues.

If you know Merchant Automotive, then you know that we never leave well enough alone. We’re not the kind of people that simply deal with these annoying issues, we solve them. We’re the leaders in Duramax engines for a reason and we’ve applied our many years of experience to this simple to install filter head rebuild kit.

We’re going to cover everything you need to know about the fuel filter head on your 2001 - 2010 Duramax truck:

• What Does A Filter Head Do?
• What Are The Signs Of Fuel Filter Trouble?
• What Is A Fuel Filter Rebuild Kit?

Ready to solve your problem? Let’s dive right in!

What Does A Fuel Filter Head Do?

The design of the Duramax engine is both a blessing and a curse when it comes down to long-term durability and overall system efficacy. Most common rail diesel trucks utilize a lift pump that moves fuel from the tank to the high-pressure fuel pump. However, on Duramax trucks, the CP3 pump is responsible for moving fuel from the tank, all the way to the pump itself! This process relies on maintaining a vacuum, or the absence of air, to get the fuel from the tank to the CP3 pump.

On one hand, the system eliminates the need for a lift pump, thus eliminating components that may wear over time. On the other hand, this design puts additional stress on the CP3 pump and is susceptible to losses of vacuum. One of the primary places that the system can lose vacuum is the fuel filter head, however, maintaining a vacuum is not the only purpose of this part.

Here are the 3 main purposes of the fuel filter head:

1. Primarily, it is the location for the fuel filter on the Duramax
2. When changing out the fuel filter or if vacuum loss occurs, it houses a primer pump
3. In order to operate in colder temperatures effectively, this component also hides the fuel heater.

As you can see, this simple part is quite crucial to the overall smooth and reliable operation of your diesel truck.

What Are The Signs Of Fuel Filter Head Trouble?

From your truck not starting after being parked on a hill, to the engine quickly dying off after starting; dealing with the issues can become frustrating and possibly leave you stranded far from home, here are the most common symptoms of issues with your filter head:

Your Truck Won’t Start After Sitting On A Hill

This one is quite frustrating and can come as a surprise to most owners. This is primarily due to worn seals that let air into the fuel system. Once fuel is drained out of the fuel lines and back into the tank, it can exacerbate the loss of vacuum and cause your truck to not start.

Start, then Immediate Stall

If your truck is stalling out immediately on flat ground, then your problem has progressed further. The same logic as your truck sitting on a hill applies here, except that the leak is worse and your engine is sucking in air, which will cause it to immediately turn right back off.

There’s Fuel Pooling Near The Bleeder Screw

Take a look at the area around your fuel filter head, and check for fuel near the top side of the assembly, near the bleeder screw. If you see any fuel in this spot, this is a sure-fire sign that your system is leaking.

The Manual Hand Primer May No Longer Be Able To Create The Vacuum Needed To Prime The System

Once you replace the fuel filter, you’ll need to prime the system manually with a hand pump on filter head assembly and then bleed out air through the screw. If you find that you are not able to create a vacuum during this process, you have a leak.

What Is A Fuel Filter Rebuild Kit?

In order to mitigate leaking issues, Merchant Automotive has created two comprehensive rebuild kits, depending on what year your Duramax truck is. If your truck is a 2001 - 2010, our complete rebuild kit gives you everything you need to complete this relatively simple job with ease. If you’re running a 2011 - 2016 Duramax, don’t worry, we have you covered here as well with a separate comprehensive rebuild kit.

This kit gives you everything you need to rebuild your filter head and eliminate any pesky vacuum leaks that are causing your engine to gulp in air. Rather than purchase the entire assembly, these rebuilding kits help you save some serious cash. How much cash are we talking about? How about several hundred dollars!

Each kit comes with the following components:

• Fuel Filter Head Rebuild Kit
  • U Shaped Seals (qty. 2)
  • Internal Seals (qty. 3)
• Merchant Automotive Aluminum Bleeder Screw
• Water in Fuel Plug
• AC Delco OEM Replacement Fuel Filter
• Fuel Filter Head Spacer Kit
• Bottle of Merchant Automotive Additive

These components are designed to replace factory components with OEM or better than OEM quality in order to minimize the chance of future failure and the issues that come along with it. A great example of this type of higher craftsmanship is our replacement of the plastic bleeder screw with a higher-quality aluminum bleeder screw that is much more durable than the OEM unit.

We also include some additional kit that makes owning and maintaining your diesel truck just that much easier. For example, take a look at our spacer kit. This clever device moves the fuel filter away from the valve cover and makes it easier to get a wrench in to remove newer, longer filters. We even throw in a bottle of our awesome Merchant Automotive Diesel Fuel Treatment Additive as well.

Overall, this comprehensive kit is a great investment for anyone who’s looking to head off issues or repair issues they’re already dealing with.

Trust The Diesel Experts

We know Duramax diesel trucks better than anyone. This includes not only the wonderful things about these workhorses but also the common problems that somehow made it through the engineering process at General Motors. We don’t just fix the problem and wait for it to happen again. We engineer specific componentry that is designed to eliminate common issues from occurring. This is the Merchant Automotive difference and what makes us so unique. We help hands-on, wrenching wielding, Duramax lovers get the most from their trucks.

If you’ve got a Duramax truck, Merchant Automotive should always be your first stop. You won’t find a better selection of products anywhere. We put our name on it.