2021 GMC SIERRA 1500 Complaints

My car suffered a catastrophic engine failure, metal schards were found in the oil filter and was left out of the 2021 recall 25V274. The in service date of vehicle is March 13, 2021. The car was 83 days out of warranty when the engine failed. The truck has 47,000 miles on it. They are now trying to charge us, barter with us. They have gone from $2800 for repair, negotiated down to $100 to sign this off as a good will repair stripping us of lemon law rights and future recall remedies. Car is currently sitting at the dealership.

The contact owns a 2021 GMC Sierra 1500. The contact stated that while driving at an undisclosed speed, the "Add oil to engine" message was displayed. The vehicle was driven to an AutoZone within two minutes and turned off. Upon inspection of the engine oil level, the contact observed that the dipstick was completely dry. The dealer was notified of the issue, and an appointment was scheduled for an oil consumption test. The vehicle was not yet diagnosed or repaired. The contact stated that the vehicle had been serviced for a routine oil change on April 21, 2026, at 53,590 miles. The contact related the failure to NHTSA Action Number: RQ26001(ENGINE). The manufacturer was not made aware of the failure. The failure mileage was approximately 56,802.

I own a 2021 GMC Sierra AT4 3.0L Duramax (VIN [XXX]). The vehicle has codes P1098 (Coolant Control Valve Performance) and P129F which coincides with the first code. My dealer believes this is consistent with an Engine Coolant Control Valve failure. I understand Special Coverage XXX exists for this issue, but I've been told my VIN is not included. My truck has the exact engine, symptoms, and diagnostic codes addressed by Special Coverage N252508341, but my VIN is excluded. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Since purchase of my 1500 Sierra 6.2L on 10FEB2021, the vehicle has always appeared to burn an excessive amount of oil which is consistent with GM’s 6.2L engines and has created safety issues leading to sweeping recalls on this engine model from 2021-2024. I have been informed that the engine was consistently down 2+ qts of oil at every recommended oil change (approximately every 5000mi) although GM literature indicated that this level of consumption was usual in their 6.2L engine. In a JAN26 oil change at approximately 35,000mi I was told that my engine was down over 3qts of oil. On 17FEB2026 I took my vehicle into my Chevy/GMC Dealership to request an oil consumption test at ~35, 089mi. On 30JUN2026 I returned to the dealership for my 2000mi check-in, at ~37,800mi, and was informed that my vehicle had failed the consumption test. With over 600,000 vehicles recalled since 2024 in the 6.2L category, my vehicle/VIN has never been associated with a recall. Despite having minimal miles on this engine, I am now financially penalized for repairs because I had just exceeded the initial Powertrain Warranty and my extended warranty would not cover a pre-existing condition. GM’s 6.2L engines have pre-existing issues from the factory and represents a danger to consumers and the driving public because of these failures.

2021 GMC Sierra after purchase at 4,700 miles had issue with the lifter rods and were replaced at that time. Now the truck has a little over 67,000 miles and once again have the same issue. This appears to be a known issue with this truck and the 5.3L engines. The truck is in repair and since it is slightly over its warranty of 60,000 miles. The dealer will not cover the repair. Seeing that this is an ongoing and known issues with service bulletins it seems that this should be a potential recall. We were lucky that we identified the issue early and were able to get to the dealer to fix. Otherwise we could have broken down in the middle of our daily commute in the expressway.

There is a water leak in the rear passenger compartment of my vehicle. Unsure where water is coming from. Continued leaking poses a risk to my safety as I may be exposed to black mold as well as anyone else who is riding in my vehicle. The problem hasn’t been addressed by the dealer yet but this is a known issue. At this point I have spoken with a representative from the service department at the dealership but cannot get an appointment for several weeks. I was also advised that the problem would need to be diagnosed before being addressed at my cost due to being outside of the warranty period. There were no warning lights or any other signs that this is occurring and was only discovered because I was putting something in the back seat on 6/26/26.

When I put the vehicle in park, the dash warning says it is not in park or shift to park. The components continue to work. I have taken it to the dealership and according to the service manger, this is a very common occurrence in these trucks. This seems to me that it would be a very serious safety issue if one assumes their vehicle is in park and it is actually not. The shift to park warning is a safety warning to alert the driver it is not in park so the vehicle doesn’t roll off and hit someone (especially a child playing in the driveway). Assuming that alert is just a malfunction could get someone killed. I did notice that this was considered a safety recall for some models of GMC vehicles but not others. I’m not sure why there hasn’t been a recall on these trucks when the service manager specifically said they are having this issue on a lot of trucks.

My truck went into Reduced Power Mode while driving on the highway (Very Dangerous and life threatening) for a Coolant Control Valve Failure code (P1098), which has been confirmed by a GM dealership. GM already has extended the warranty for Special Coverage N252508341 for selective Vin numbers only and my Vin number is being excluded which isnt safe at all or fair. My truck is a 2021 Sierra Denali 3.0L lm2 duramax and has the same exact problem (coolant control valve failure code), and the same exact faulty part, and the same exact motor (LM2) which directly matches the perimeters for the N252508341 Special Coverage Program but my truck isnt being recalled or covered for repair due to them selectively choosing certain Vin numbers to recall only.

The AFM caused piston flapping and other major engine problems such as abnormal wear. The problem with the engine could have caused a catastrophic failure along the side of a highway. The problem has been diagnosed and the engine has been replaced at my expense. The repairs were made at a local mechanic shop. The engine would start make a loud ticking noise at 2000 RPM or above. The mechanic shop referred to this as piston flapping. This was caused by inadequate oil pressure at all cylinders due to the Active Fuel Management.

The contact owns a 2021 GMC Sierra 1500. The contact stated that while driving at an undisclosed speed, the brake pedal was depressed, but the vehicle continued to move forward. There was no warning light illuminated. The vehicle was taken to the dealer and was diagnosed with transmission failure. The contact stated that the valve body and torque converter needed to be replaced. The dealer informed the contact that the transmission might need to be replaced. The vehicle was not repaired. The manufacturer was not made aware of the failure. The failure mileage was approximately 65,561. The VIN was unavailable.