Common Issues and Solutions for Duramax Diesel Engines

Close-up picture of new and old fuel injector | Branch Automotive in Highlands Ranch

Common Issues and Solutions for Duramax Diesel Engines

Common Issues and Solutions for Duramax Diesel Engines

Common Issues and Solutions for Duramax Diesel Engines

Since 2001, Duramax engines have been known for delivering exceptional diesel power and performance for Chevrolet and GMC vehicles. While Duramax diesel engines are generally reliable, there are some common Duramax diesel repair issues that owners should be aware of. In this post, we’ll explore some of these issues and the solutions offered at Branch Automotive in Littleton, CO.

Glow Plug Replacement Is a Common Duramax Diesel Repair in Littleton, CO & Highlands Ranch, CO

No matter the type of diesel engine you have in your truck, glow plugs or heating elements are fundamental. Glow plugs are responsible for heating the combustion chamber, air, and fuel to bolster combustion efficiency. If your Duramax diesel engine’s glow plugs begin to fail, it can cause several problems, including:

  1. You notice a drop in fuel efficiency.
  2. Your engine may start misfiring.
  3. Your engine may begin hard starting or rough idling.
  4. Your exhaust is smokier than it used to be.
  5. Your truck’s check engine light may be on.

Every diesel truck will eventually need glow plug system repairs.  Older trucks may not set a check engine light, however you will notice they are hard to start when the temperatures start to drop.  Newer trucks will set a check engine light for glow plug performance – this could be an indication of failed glow plugs, failed wiring, a failed control relay, or a failed glow plug control module.

How to Handle Duramax Diesel Engine Glow Plug Problems?

The first step is to always evaluate the vehicle and determine what the actual failure is. Once identified, repair or replace the failed component(s) and retest the system for proper operation.  In many cases you will find that a glow plug or multiple glow plugs have failed, however it could be the control module, or even a wiring fault.  If it is determined that a glow plug or multiple glow plugs have failed, then our recommendation is to replace all eight glow plugs, because they all have the same mileage and wear, and will start to fail later one or more at a time until they have all been replaced.

Fuel Lift Pump Problems in Littleton, CO & Highlands Ranch, CO

While some Duramax problems are limited to specific model years, fuel pump failures are prevalent for all years. The Duramax diesel engine utilizes a direct injection fuel system. One of the most critical parts of this system is the fuel injection pump.

The CP3/CP4 fuel injection pump comes standard on Duramax engines. This fuel pump provides the fuel to make the engine run, but also utilizes fuel for cooling and lubrication of the pump and injectors. Until recently, the fuel system lacked a transfer pump in the tank. This forced the injection pump to not only generate high-pressure fuel for the injectors but also to pull the fuel from the tank, essentially doing twice the work.

How to Fix the Duramax Diesel Engine Fuel Lift Pump Problem?

As most would assume, the best way to remedy this problem is to add an aftermarket lift pump. Adding an aftermarket lift pump can prevent other issues, extend the life of fuel injection components, reduce emissions, and ensure proper engine performance.  Adding a lift pump to a Duramax that previously didn’t have one is a great addition to the truck to ensure longevity and keep the truck on the road. Adding a lift pump wont add power to the vehicle, but it will ensure the injection system has all the fuel that it needs to do its job correctly.

Water Pump Problems Can Lead to Duramax Diesel Repair in Littleton, CO & Highlands Ranch, CO

The water pumps on newer Duramax diesel engines feature plastic impellers. Like many plastic parts, these impellers are weak and more prone to failure. In some instances, the water pump impeller can spin on the driveshaft, causing poor coolant flow and poor cooling system performance.  At the same time, the water pump used in the Duramax diesel engine can leak externally, which can and often leads to overheating problems. Problems with your water pump can also negatively impact the pressure of the system, which can lead to coolant supply inadequacies.

How to Fix Duramax Diesel Engine Water Pump Problems?

We start by evaluating the cooling system performance and condition This is the best way to determine if a leak is causing pressure and fluid loss, if the issue is a flow issue, or if the system is unable to remove the heat from the coolant before sending it back to the engine.  Evaluation is always step number one because modern cooling systems are complicated, and there is no magic bullet that fixes all cooling system issues. If a water pump replacement is necessary, we use water pumps that feature metal impellers to remove the possibility of a plastic impeller failing internally. 

Fuel Injector Problems Are a Common Duramax Diesel Repair in Littleton, CO & Highlands Ranch, CO

Every diesel owner will replace fuel injectors if the vehicle has enough mileage put on it.  Injectors are hour rated and have a service life like everything else.  On the Duramax engine, the fuel injectors are injecting fuel at up to 26,000 PSI and over time can develop ball and seat erosion, leading to improper injection quantity or the inability to stop the flow of fuel into the engine if the wear gets too bad. This can lead to;

  1. Excessive smoke
  2. Rough idling
  3. Loss of power

How to Solve Fuel Injector Problems on the Duramax Diesel Engine?

If you suspect injection system problems in your Duramax, testing and inspection is critical.  There isn’t much of anything that can be evaluated visually.  The injectors must be evaluated for balance rates, as well as checking many other items like fuel system vacuum, evaluating for any leaks, inspecting the ability of the injection pump to supply the correct volume and pressure of fuel, and evaluating for any excessive smoking from the exhaust among other things.  Injection system components are expensive, and we want to make sure that we’re going to correct the concern in the system. After the failure has been identified, replace the failed components and re-evaluate the system for proper performance then return the vehicle to you where it belongs.

Contact Branch Automotive for Duramax Diesel Repair in Littleton, CO & Highlands Ranch, CO

When it comes to finding the best diesel engine repair solutions, tthe team at Branch Automotive will meet your needs and exceed your expectations. We offer a full range of diesel repair solutions for all diesel engines, including Duramax diesel enginesPowerstroke diesel enginesCummins diesel engines, and more!

Contact Branch Automotive today! Call (303)771-2224, visit us at 6030 E County Line Road in Littleton, CO, or complete our online contact form.