2021 Chevrolet Silverado 2500 Engine Problems

The contact owns a 2021 Chevrolet Silverado 2500. The contact stated that while driving 15 MPH, there was a knocking sound coming from the engine. The vehicle was taken to the local dealer, and the contact was informed that the engine was blown causing complete engine failure. The engine was replaced under warranty, but the failure reoccurred. The warranty company inspected the vehicle. The failure mileage was approximately 121,000.

NHTSA ID

11767683

Incident

Jun 22, 2026

Mileage

121,000 mi

Similar to the issues that were on the gas version of this engine and the recall associated with it. The engine seized on the expressway. When it was towed to the dealership, they said it was catastrophic engine failure. They found a lot metal shavings in the oil pan. They did not diagnose any further due to cost. At the time it happened, there were no warning lights or check engine lights on.

NHTSA ID

11724650

Incident

Mar 11, 2026

first issue was around April-May 2025 when my engine started knocking and burning fuel. Warning light came on and it went right in to the dealer where I have all my maintenance done. They determined that it due to (2) faulty fuel injectors and I had them replaced at that time. In December of 2025 my engine started doing the same thing as before with the knocking and burning fuel and reduced speeds when on the highway so again it went into the dealer. It has since been in there and first was told it was the fuel injector again. They priced out the one was bad and I asked them to replace the remaining 6 fuel injectors so I didn't have this issue again in the near future. They did and the vehicle had the same issues going on. During the next inspection it was determined that the engine needed new rocker arms. These were replaced but this also did not solve the problem and the vehicle would not pass the regeneration on the engine. During the next inspection it was determined that we needed to replace a cylinder and one of the valves. After this was complete they were still having issues and then I was told that the Piston was bad and there are (2) bad valves so I need an entire engine replacement. My truck only has 130,000 miles and has been in the shop for almost 2 months last year from engine issues and it has had all maintenance completed at he same dealership with Records.

NHTSA ID

11711815

Incident

Dec 5, 2025

I own a 2021 Chevrolet Silverado 2500HD Duramax diesel with approximately 100,300 miles. The truck began displaying a “Service Emissions System” warning and a countdown message that in a certain number of miles the vehicle will be limited in speed (for example to 65 mph). GM’s own Duramax diesel owner’s supplement explains that when a “Service Emission System” message appears it is accompanied by a distance-until-speed-limit countdown and that the truck will progressively limit speed first to about 65 mph and then to about 55 mph if the condition is not corrected, telling the owner to see the dealer. This creates a safety risk because the derate can occur while driving on highways or rural roads, where an unexpected limit on maximum speed can interfere with merging, passing, and keeping up with traffic. This is our only vehicle, and we must use it for important medical appointments, including cardiology and surgery-related visits. The condition started only about 300 miles beyond GM’s 5-year / 100,000-mile powertrain warranty. I opened a case with Chevrolet / GM Corporate (Service Request No. XXX) and took the truck to Sons Chevrolet in Columbus, Georgia on November 17, 2025 for this issue and a rear wheel lockup recall. The dealer kept the truck from about 9:00 a.m. to 3:00 p.m. and indicated they might need to keep it for at least two more days, but I was not given a clear written explanation of the diagnostic trouble codes or a firm repair plan. Because GM’s own manuals describe this “Service Emission System” message together with speed-limit countdowns, and because the vehicle can actively limit speed on the road if the fault is not resolved, I am concerned this represents a broader emissions/derate defect on late-model Silverado HD Duramax trucks. I request that NHTSA review similar complaints and consider whether further investigation or a safety recall is warranted. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11700011

Incident

Nov 17, 2025

The contact owns a 2021 Chevrolet Silverado 2500. The contact stated that while slowing down and coming to a stop, the accelerator pedal was depressed while in drive; however, the vehicle started to roll backwards. The contact depressed the brake pedal to prevent the vehicle from rolling backwards, and the RPM became elevated to 5,000 RPM. The contact immediately turned off the vehicle to prevent the RPM from continuing to increase. The vehicle was shifted to park, restarted, and then shifted to drive(D) and the brakes released. While releasing the brake pedal, the failure reoccurred. The vehicle was immediately turned off and towed to the residence. The dealer was informed of the failure of the clutch pack, which was welded together from friction. The dealer scheduled an appointment; however, the vehicle was not diagnosed or repaired. The manufacturer was not informed of the failure. The failure mileage was approximately 100,000.

NHTSA ID

11698898

Incident

Nov 7, 2025

Mileage

100,000 mi

JULY 2022 DPF filter was throwing check engine light. Took to dealer to get diagnosed, part was ordered and the DPF was replaced August 19th 2022. Started to get headaches in vehicle while driving it. OCT 9th ended up in hospital after driving vehicle and was diagnosed with CARBON MONOXIDE POISONING. Experienced symptoms of losing consciousness, worst headache I've ever had, nausea for 5 hours, loss of feeling in body and seizing of body. Took truck to dealer to get inspected twice and nothing was found to be wrong with it. NOV 10th Took truck on another road trip and was having similar symptoms as before however had more chest pain this time so went back to hospital. Took truck back to dealer to have inspected again and was told that it was fine. Nov 18th took truck on another road trip and within 20 mins of driving had another horrible headache. Pulled over and needed to get air and ended up driving truck 4 hours home with windows and sunroof open to avoid getting carbon monoxide poisoning again. I have been ill since August and that is due to diesel and carbon monoxide poisoning every single time I drive the vehicle which is daily. The truck has been now at the dealership for 70 days without any update or improvement in the case.

NHTSA ID

11504538

Incident

Aug 19, 2022

MY TRUCK WILL NOT START RANDOMLY. THE TRUCK WILL CRANK BUT WON'T FIRE. IF I WAIT A WHILE IT WILL EVENTUALLY START. I TOOK IT TO THE DEALER AND WAS TOLD THAT THEY COULD NOT RECREATE IT. NO CHECK ENGINE LIGHT ON AND NO ERROR CODES NOTED.

NHTSA ID

11406258

Incident

Apr 3, 2021

Mileage

4,200 mi

6.6L GAS TRUCK WOULD NOT START. FORUMS IVE VISITED STATE THIS IS A KNOWN PROBLEM WITH THE ECM. AFTER APPROX 30MINS IT STARTED. HOWEVER BEFORE THAT IT SPUTTERED OUT EVERY TIME I WOULD TRY TO START IT. IT APPEARS TO BE AN INTERMITTENT PROBLEM. IT RAN FINE ONCE IT EVENTUALLY DID START. ALSO AUTO START WOULDN'T ENGAGE WHEN THIS PROBLEM WAS OCCURRING.

NHTSA ID

11388641

Incident

Jan 17, 2021

Mileage

1,656 mi