mobile-menu-icon
GM Authority

GM Duramax Diesel Engine Maintenance Explained: Video

Opting for a Duramax diesel engine in a new GM SUV or truck is a great choice for those customers that want both torque and efficiency, and now, GM is detailing a few simple maintenance tips to keep the Duramax diesel powerplant running in tip-top shape.

As seen in the following four-minute video, maintenance tips include how to refill the Diesel Exhaust Fluid, or DEF, as well as how to change the fuel filter.

For those who may be unaware, DEF is used to reduce the amount of harmful pollutants (NOx) present in diesel exhaust gasses. GM recommends that owners only use GM-approved DEF from a GM dealership. To refill this critical fluid, first open the fuel DEF door to access the DEF filler. In some vehicles, the DEF filler is located in the engine compartment. The DEF filler cap is typically blue and labelled “DEF.” After locating the cap, turn it counter-clockwise and remove it.

Next, use a funnel to prevent spilling DEF, then pour in fluid until it reaches the bottom of the funnel. Do not overfill. GM advises that there may be a delay in detecting the current DEF level, which is displayed in the gauge cluster Driver Information Center (DIC). Make sure to wipe away spills with a damp cloth, then close the DEF filler cap.

Next, the video goes over what it takes to change the fuel filter on a GM vehicle equipped with a Duramax diesel engine. GM advises that the fuel filter is typically located on the underside of the vehicle, either on the driver’s side along the frame rail, or behind the rear axle. More information can be found in the vehicle owner’s manual or in the Duramax diesel supplement.

Before changing the fuel filter, make sure the engine is turned off and the parking brake is on. GM also advises that area around the filter should be cleaned of any possible contaminants.

Next, drain any water from the fuel filter by either loosening the fuel filter cap with a hex tool or Allen wrench, then draining fluid into a catch pan. After removing the filter cap, remove the old filter element and o-ring. Make sure there’s no dirt around the cap, then place a new o-ring around the cap and apply some lubrication. Make sure there’s no dirt or contaminants inside the cap either. Finally, slide a new filter element into the cap, making sure not to damage the water sensor probe, and reinstall the assembly, prime the system, and reset the fuel filter life remaining percentage on the DIC.

Check out the full tutorial video right here:

Subscribe to GM Authority for more GM technology news and around-the-clock GM news coverage.

Jonathan is an automotive journalist based out of Southern California. He loves anything and everything on four wheels.

Subscribe to GM Authority

For around-the-clock GM news coverage

We'll send you one email per day with the latest GM news. It's totally free.

Comments

  1. You want me to crawl underneath my truck to access a fuel filter? Really?

    Reply
    1. Where do you think they put fuel filters in cars?

      Worse, you’ve obviously never had a vehicle with an in-tank filter: Pull out the whole rear seat, disconnect the fuel lines with the special tool, take the whole pump module out, pick out the filter, change the gasket, follow the exact torque and tightening sequence, leak check the connections, and deal with the interior of your car giving you gasoline fume headaches for the next week.

      Reply
      1. Even better, on the old S-10’s I had to remove the bed to get to the fuel pump and screen assembly inside the tank. It wasn’t as bad as it sounds, it was a short bed so just 6 bolts and some wiring connectors. Then I removed the tailgate and it lifts right off with a couple of extra hands.

        Reply
  2. “GM recommends that owners only use GM-approved DEF from a GM dealership.”
    Just another way for GM & other automakers to rip you off.
    Blue Peak DEF or any DEF meeting the industry standard will work just fine.

    Reply
    1. It’s called capitalism. Get used to it.

      Reply
      1. Ha! Not many fans of capitalism here, given the number of downvotes I’ve gotten….

        Reply
        1. Nah. It’s called freedom of speech.
          You are allowed to make a comment of no benefit to anyone.
          We’re allowed to down-vote it.

          Reply
  3. If you need instructions on filling def please do us all a favor n buy a gas! Anyone with a smidge of mechanical ability can change a fuel filter. If you can’t find waldo( fuel filter) please buy a gas or go to dealer! 🤷🏻‍♂️

    Reply
  4. savin the world one cardboard box & plastic jug at a time

    Reply
  5. If you are a newbie to diesel you should’ve done your homework before buying, or as one said take it to the dealer. Diesel ain’t gas, even gas has to have filter changes just not as a often.

    Reply
  6. GM has a warranty requirement to use only GM approved DEF. I was using Peak for awhile, but noticed that the engine used a lot more than it did when using Delco. It makes a big difference, especially when towing a travel trailer. When using Peak, it would use one full bottle inside of 400 miles. With Delco it consumes less than half that amount. All I’m saying is that I see a big difference in brands.

    Reply
    1. First, they do not. They can only require API approved DEF. It’s the only thing the EPA will allow them to say, as DEF is emissions-related.

      Second, they’re the same thing. Read the SDS for the AC Delco stuff: it’s made by Old World Industries, the same company that sells Peak branded products. OWI is also the supplier for Wal-Mart’s SuperTech brand.

      You’re probably measuring it wrong. First, you need to measure DEF consumption as a percentage of fuel consumption, not miles. Second, the cluster gauge is an idiot light and has mileage compensation. If you want to measure your actual consumption accurately, you need to read tank levels from an OBD scan tool.

      Reply
      1. When it shows up on your dash/DIC that the DEF level is low when it really isn’t gm has a service bulletin to update the software, don’t waste your time. I had/have this issue and had the service bulletin performed and it didn’t fix anything and still does the same thing.

        Reply

Leave a comment

Cancel