Nov 19, 2018 · The 2019 Diesel Supplement might be different from prior issues. I just took delivery on a 2500 L5P. My Supplement recommends Top Tier Diesel which is almost impossible to find nationwide and if Top Tier is not available "GM recommends the use of ACDelco Diesel Fuel Conditioner" GM naturally does not recommend other aftermarket additives.

Jul 20, 2022 · Looking at a L5P Duramax. Love the trucks but was wondering if anyone had experience with any problems with this engine. Sent from my iPhone using Tapatalk

Sep 20, 2022 · Duramax Diesel Engine Oil Filter Update for 2023 September 20, 2022 The PF63 engine oil filter (Fig. 5) is the new recommended filter specification for 2020-2023 Silverado 2500HD/3500HD, Sierra 2500HD/3500HD, Express, Savana; and 2019-2023 Silverado 4500/5500/6500 models equipped with the 6.6L Duramax diesel engine (RPO L5P, L5D).

Jan 24, 2025 · Hello everyone. I am new to the forum. I have a 2017 L5P that a purchased a few months ago and started losing coolant recently. I brought it into 2 different diesel shops and both said either cracked head or head gaskets. Was thinking of tackling the job myself. Does the cab have to come off to do?

Jul 3, 2022 · After 153K miles my faithful Duramax gave me the infamous emissions service countdown. I went to my local GMC dealership for a diagnostic check, and they said the reduction tank heater was not working and suggested replacing the Emission Reduction Fluid Supply Pump Module, part number 84545446...

Jan 2, 2025 · Do you start using fuel additives immediately on new engines? Just picked up a new ‘25 L5P Silverado with 12 miles and wondered when would be best to start the additives. Our other diesels were purchased used (‘23 LM2 and a 5.9L Cummins truck) so I started using additives immediately...

Mar 10, 2025 · A forum community dedicated to Chevy and GMC Duramax diesel owners and enthusiasts. Come join the discussion about modifications, towing, classifieds, troubleshooting, maintenance, and more!

Feb 17, 2020 · Anyone run into this on a l5p? Fuel rail pressure performance during deceleration. Data shows rail pressure bouncing 3 to 4k during 0% throttle deceleration. Desired at 10200 and actual will bounce 9 to 13k. Bone stock truck with 143,000 miles. …

Jan 22, 2024 · I run DuramaxTuner (Calibrated Power) SOTF tunes on my 2017 L5P. The ECM/TCM tunes definitely significantly improved power and responsiveness, but I haven't seen any significant change in mileage, towing or unloaded.

Aug 31, 2024 · Not a deal breaker. But my new Duramax's fuel economy is about 3 MPG less then my last 6.7 Cummins. I have heard the generation 1 L5P's were much better in the fuel economy arena. Has anyone found a remedy to correct this?