2021 GMC SIERRA 1500 Complaints

The contact owns a 2021 GMC Sierra 1500. The contact received notification of NHTSA Campaign Number: 25V274000 (Engine and Engine Cooling). The contact stated that while driving at approximately 50 MPH, there was a loud squeaking sound coming from the front driver’s side of the vehicle before the vehicle lost power. Simultaneously, the check engine warning light started blinking. The vehicle was pulled over to the side of the road and the sound became louder, before becoming a knocking sound. The vehicle was restarted, and the failure persisted. The vehicle was towed to the residence. The vehicle was not diagnosed or repaired, but a dealer stated that there was as recall associated with the VIN; however, parts were not yet available to repair the vehicle. The manufacturer was not notified of the failure. The failure mileage was approximately 128,000. VIN tool confirms parts not available.

Was informed from by GM that my vehicle is involved with a recall an still hasn't been repaired

What component or system failed or malfunctioned, and is it available for inspection upon request? The valvetrain system failed due to broken rocker arms, which resulted in additional internal engine damage. This failure occurred under normal driving conditions. The affected components have not yet been discarded and are available for inspection upon request.How was your safety or the safety of others put at risk? The failure caused sudden engine misfiring and knocking, reducing engine power while I was operating the vehicle. This significantly compromised acceleration and response time, especially during merging and lane changes, which could have led to an accident. Any unexpected loss of power or engine instability at highway speeds poses a serious risk to myself, passengers, and other motorists.Has the problem been reproduced or confirmed by a dealer or independent service center? Yes. The issue has been diagnosed and confirmed by an independent certified mechanic, who verified the broken rocker arms and resulting engine damage during inspection.Has the vehicle or component been inspected by the manufacturer, police, insurance representatives, or others? The vehicle has not yet been inspected by the manufacturer, police, or insurance representatives. Only a certified independent mechanic has inspected the failure thus far.Were there any warning lamps, messages, or other symptoms of the problem prior to the failure, and when did they first appear? Yes. The check engine light appeared and the engine began running rough and producing a knocking sound. These symptoms occurred just prior to the confirmed failure and prompted me to stop driving the vehicle immediately and have it inspected. Given the seriousness of this issue and reports from other GMC 5.3L engine owners experiencing similar rocker arm failures, I urge the NHTSA to investigate this potential defect. It poses a real and significant safety risk.

On Dec 27 I noticed a skip in my engine when I started the truck. I took the truck to Cronic Buick GMC on Jan 6 for an inspection. They reported to me that the engine failed.Seized up. I reported the incident to my extended warranty company Warranty Solutions. They refused to do the repair because I was late for an oil change in 2022. After 3 weeks and no cooperation I contacted GM customer service. I was assigned an agent that help initiate the engine repair . The repair was completed on April 12 (3 months after the failure). I paid $4600 out of pocket for a portion of the engine repair .

The contact owns a 2021 GMC Sierra 1500. The contact received notification of NHTSA Campaign Number: 25V274000(Engine and Engine Cooling); however, the part to do the recall repair was not yet available. The contact stated that while driving at approximately 60 MPH, the check engine warning illuminated and the vehicle stalled. The contact pulled to the side of the road and attempted to restart the vehicle, but the vehicle failed to restart. The vehicle was towed to the residence. The contact stated that the failure had previously occurred several times while driving. An unknown local dealer was contacted and informed the contact that the recall parts were not available. The vehicle was not diagnosed or repaired. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The manufacturer was contacted and a voicemail message was left, but the manufacturer had not returned the contact's call. The failure mileage was approximately 70,000. VIN tool confirms parts not available.

Replacement part needed is COOLANT CONTROL VALVE according to diagnostics at local GM dealer service department after noting check engine light was on. YES, it is available for inspection. Told unsafe to drive as it would very likely overheat or worse. It has been in the shop for a month (as of June 11, 2025) awaiting a backordered part, which we’re told is a national backorder. No loaner vehicle available and told by service department that they have had another truck in for same problem for several months and that this problem is very common. PLEASE HELP us with getting the part needed!

The contact owns a 2021 GMC Sierra 1500. The contact received notification of NHTSA Campaign Number: 25V274000 (Engine and Engine Cooling); however, the part to do the recall repair was not yet available. The contact stated that the vehicle was experiencing rough idling, with the RPM fluctuating while driving. The local dealer was contacted. The vehicle was not diagnosed or repaired. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The manufacturer was not made aware of the issue. The failure mileage was approximately 32,000. VIN tool confirms parts not available.

The coolant control valve is faulty and is on national backorder causing months of my truck sitting in the shop. This is not an isolated issue. GM is claiming it is not covered under warranty, but the part design is clearly a serious issue.

The contact owns a 2021 GMC Sierra 1500. The contact stated while driving 75 MPH, the vehicle jerked and downshifted to overdrive. The message "Engine Power Reduced" was displayed on the instrument panel. The driver depressed the accelerator pedal, but the vehicle failed to exceed 4 MPH. The vehicle was taken to the dealer, where it was diagnosed that the valve body failed, which caused the transmission to fail. The vehicle was repaired. While the contact was driving home after the vehicle was picked up, the vehicle jerked and hesitated. The dealer was contacted and informed the contact that if the check engine warning light becomes illuminated the vehicle could be diagnosed. After several days, the check engine warning light illuminated, and the vehicle was taken to the dealer where it was diagnosed that the shutter valve had failed and needed to be replaced. The vehicle was repaired. The contact stated that the failure persisted. The contact received NHTSA Campaign Number: 24V797000 (POWER TRAIN). The vehicle was repaired; however, the failure persisted. The manufacturer was made aware of the failure and offered the contact assistance with the transmission repair. The failure mileage was approximately 119,000.

The contact owns a 2021 GMC Sierra 1500. The contact stated that upon starting the vehicle, there was an abnormal knocking sound coming from the engine. The abnormal sound ceased once the vehicle had accelerated; however, the abnormal sound returned while the vehicle was idling. The check engine warning light was illuminated. The vehicle was taken to the dealer where it was diagnosed that the ball bearing caused a misfire, and two cam lifters needed to be replaced. The vehicle was repaired. The contact picked up the vehicle and on the way home, the engine failed. The contact took the vehicle back to the dealer. The technician test drove the vehicle with the contact as a passenger, and the check engine warning light illuminated. In addition, there was an abnormal sound coming from the engine. The vehicle failed to accelerate as intended while depressing the accelerator pedal. The contact was informed that the engine failed and needed to be replaced along with the fuel body system. The contact was informed that as per GMC, the oil needed to be changed to an oil with a thicker viscosity. The fuel body was replaced, and the oil was changed. The manufacturer was made aware of the failure and offered the contact an amended warranty. The contact was informed that GMC had elected to participate in the procedures under the Song Beverly Act. The failure mileage was approximately 50,000.