2021 GMC SIERRA 1500 Complaints

-The engine in my 2021 GMC Denali 1500 with the 6.2L engine failed its second engine with ~4,000 miles on the new engine. It is currently at GMC dealer waiting for a 3rd new engine. - Fortunately i was parked when the failure happened and the engine locked up. -Dealer confirmed that a valve dropped and damaged the cylinder wall. - There were no warning lamps or other indication that a failure was about to happen. -Current mileage ~91,000. First motor changed ~85,000 due to recall with previous owner.

There is a recall on the 6.2 motor that is in my truck at my last oil change they performed a pico scoop diagnostic on the truck said it passed and gave it the new type of oil and oil cap that was suppose to fix it. Now a couple months later I walk out start my truck to let it warm up and after starting all of a sudden the engine started nocking bad and loss of oil pressure and on dip stick. I looked it up and this is what happens when the engine fails due to the massive recall on the 6.2 engines. I called the dealer and they are having me tow the truck potentially at my expense for them to look at and decide if it falls into the category of the recall after they did the test, and at one point told me that cause they did the test it is no longer recalled. I am being told people who have had the engines replaced because of the recall that the replacement engines have failed as well. I have a 9 month old baby and this left me stranded and unable to pick him up from daycare I had to scramble to find somone able to do so. I'm concerned that this could have happened while driving and having him with me or being left stranded somewhere.I'm glad it didn't happen when I was dropping him off that morning and while I was driving And meanwhile while they look at the issue and decide weather this falls under there recall or not and while it gets repaired I'm left without a vehicle and to be honest I don't feel safe even if they do repair it as there seems to not be an actual fix to the situation. this is unsafe and unacceptable for the price we have to pay for these rigs and the safety regulations and standards we have, how is this even an issue.

THE ENGINE COMPLETELY SHUTS OFF WHEN I STOP AT A STOP SIGN OR STOP LIGHT. I HAVE BEEN STUCK IN TRAFFIC INTERSECTIONS ON SEVERAL OCCASIONS UNABLE TO MOVE WHEN THE LIGHT TURNS GREEN. EVENTUALLY THIS WILL LEAD TO ME GETTING REAR ENDED AND PUSHED INTO IN THE MIDDLE OF AN INTERSECTION. MY LIFE IS IN DANGER WHEN I DRIVE THIS VEHICLE. I GOT MY ENGINE REPLACED AND STILL THE SAME ISSUE IS OCCURRING WITH THE AUTO STOP AND START SYSTEM.

I believe the torque converter is failing. While driving approximately 38 mph and also 48 mph up to 51 mph the vehicle have a vibration feeling like driving on a rumble strip. If you maintain the same speed, the vibration continues if you speed up, slow down, or let off the gas it goes away. There are so many detailed explanations on forums and social media from other customers experiencing the same problem, but not seeing any recall made by GMC.

P1098 code coolant control valve fail service bulletin N252508341 my vin not covered but same motor and same part !

Tires are LT275/65R20. While driving on interstate at approximately the speed limit and low 80 degree temperatures in South Carolina with proper placard pressure tire inflation checked two days prior, the truck developed a faint vibration which got worse over three or four miles. I slowed my speed and pulled over at next offramp and visually inspected truck for signs of vibration. Including looking over tires. It seemed like a drive line issue, however truck is a 2021 model with only 38,000 miles. After I could not find anything out of place I got back on the interstate to see if problems still existed. I was only traveling at 45 mph and vibration was getting worse, so I tried to slow and make it to next offramp when the driver side tire blew out causing me to have to quickly react to prevent having an accident. The tire tread and multiple parts of the truck inner fender guards and liner were thrown out into traffic and truck bed side is badly damaged. Prior to blow out there were no warnings on the dash board to to indicate any sort of issue and I verified tire pressures when I stopped after the vibration initially set in. The TPMS system was working properly at the time of the blowout. I have the tire if further inspection is warranted. My safety was at risk when tire blew out on the interstate along with vehicles traveling around me to avoid hitting the flying debris and tire tread. Further this was driver side tire and I had to change the tire on the side of the interstate with traffic right beside my vehicle. I called GMC and they said they would do nothing to help because they see tires as a maintenance item and truck is out of warranty period. I am a mechanical engineer having worked many years for major tire company as a tire design engineer. I am very familiar with load ratings, tire wear, life expectancies, and I believe theis tires failed prematurely. I bought this truck new and have always had tires properly inflated a never overloaded.

The contact owns a 2021 GMC Sierra 1500. The contact stated that while driving approximately 50-65 MPH on an incline, the contact believed that the transmission was slipping or there was a misfire coming from the engine. The contact stated that the vehicle failed to restart automatically after the engine AUTO Start/Stop system was engaged after a complete stop. Additionally, the contact stated that after driving for a while, the vehicle went into LIMP Mode. The check engine warning light and other warning lights were illuminated. The vehicle was taken to the dealer to be diagnosed. The contact related the failure to GM Campaign Number: N252515590 (Corroded Ground Strap); however, the dealer had informed the contact that the vehicle was not covered because the VIN was not included and there was no warranty coverage on the vehicle. The vehicle was not yet diagnosed or repaired. The manufacturer was notified of the failure and referred the contact to the NHTSA Hotline for assistance. The failure mileage was approximately 75,000.

L87 engine failure 4 months after it passed the recall test. Experienced shuddering and rpm fluctuation with the cruise control set. Was thinking torque converter. Got it replaced under warranty and the the issues were still there. A week after new TC the truck was running very rough driving down the road. Check engine light along with a low oil Pressure warning and Lost all engine power going 60mph. Would not re fire. Had to coast to a stop with no headlights on only fog lights. Truck is at dealership now will be needing a new engine. P0016 engine code. The truck was in the shop multiple times for misfire and rpm’s jumping and cruise control turning off on its own.

I've been to the dealership a few times due to the truck jerking violently under very light acceleration when its trying to shift gears. also there was a few times that the rear wheels have locked up while driving.

I am filing a complaint regarding a catastrophic engine failure in my 2021 GMC Sierra 1500 equipped with the 6.2L V8 engine. While driving under normal conditions, the engine suddenly failed without warning and threw a connecting rod, rendering the vehicle inoperable. There were no prior warning signs such as knocking, overheating, oil pressure issues or even a check engine light. The vehicle has been properly maintained, including regular oil changes using manufacturer-recommended 0W-40 oil. This failure created a serious safety concern due to the sudden loss of power while driving, which could have resulted in a dangerous situation, especially at highway speeds or in traffic. I am aware that General Motors has issued a recall and/or is aware of similar failures involving the 6.2L engine in certain 2021 vehicles. However, my vehicle’s build date falls just outside the currently defined recall range, despite experiencing the exact same type of catastrophic failure described in those cases. My build date is 12/20 and the recall was issued for 3/21. Given the similarity of this failure to known issues, I believe this defect extends beyond the currently identified recall population. This raises concerns that additional vehicles, including mine, are at risk of sudden engine failure without warning. I am requesting that National Highway Traffic Safety Administration investigate this issue further and consider expanding the recall to include additional affected vehicles outside the current build date range.