This truck has the 6.2L power train and the engine failed and needed to be replaced at approximately 70,000 miles. After replacement around 80,000 miles I then needed to have the water pump replaced because it failed as well.
2021 GMC Sierra 1500: engine failure
115 of the 603 complaints about the 2021 GMC Sierra 1500 describe engine failure.
- owner complaints
- 115
- of this car's complaints
- 19%
- typical repair cost reported
- $9,300
- typical mileage
- 80,000
- recalls
- 1
Engine failure by model year
What owners say
The contact owns a 2021 GMC Sierra 1500. The contact stated that while driving 45 MPH, there was an abnormal knocking sound coming from the vehicle. The vehicle started hesitating, and there was a loss of power that became worse over time. Additionally, the “Service Engine” and “Power Train” warning lights were illuminated. The messages “Loss of Steering Assist - Be Alert” and “Service Parking Brake” were displayed. The following day, the vehicle was driven in LIMP Mode to the dealer and was diagnosed with engine failure. The contact stated that there was an ongoing the federal safety agency investigation associated with the 6.2L engines. The failure mileage was approximately 34,000.
The contact owns a 2021 GMC Sierra 1500. The contact stated that while attempting to start the vehicle, the engine failed to turnover. The vehicle was towed to the residence. The contact stated that the vehicle was inspected and it was determined that the engine had seized. The engine was rebuilt and the vehicle was repaired. The manufacturer was notified of the failure. The contact associated the failure with the federal safety agency Campaign Number: 25V274000 (ENGINE AND ENGINE COOLING). The failure mileage was 142,767.
Engine locked up while driving down the road at highway speeds. Lost all power and had to pull to shoulder of road. Was towed to dealership and confirmed engine locked up and covered under special recall. Was looked at a few months back and passed the recall test on engine. No lights or signs of engine failure before failure.
My 2021 GMC 1500 Sierra has the 6.2L motor that has significant known issues with catastrophic engine failure involving the camshaft and lifters. The engine in my truck has suffered the same failure but for some reason my VIN is not included in the recall of nearly 600,000 GMC trucks. I called GMC Customer Service and was told bluntly the recall was VIN specific and I would have to bear the 14,000 dollar repair. This is unacceptable since GMC is under federal investigation for knowingly and negligently manufacturing a flawed motor.
Loud engine knock, made it to dealer. Dealer confirmed engine failure as defined in the applicable recall. No idea when a replacement can be aquired. Unable to drive anywhere due to design and manufacturinf issues I did not cause.
2021 GMC with 6.2L motor. The engine begin to produce a clattering noise in the upper part of the engine. When the clattering happens the vehicle will shudder. I took the vehicle into a certified independent service center who diagnosed a catastrophic engine failure as a result of lifter and camshaft bearing failure. They further advised that this year of vehicle (2021) and engine (6.2L) was known to have this defect and might be subject to a safety recall. I contacted GM customer service who stated that my VIN was not included in the recall even though the year and engine matched the recall. I found that to be odd especially when I noted that nearly 600K vehicles matching my failed engine was recalled. She stated that I (owner) had to bear the cost of replacing the defective engine and labor. I had to have my vehicle transported from [XXX] to [XXX] at the cost of 1400 dollars. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
While towing a trailer on 6/26/26, the 6.2L L87 engine suffered a sudden drop in oil pressure, began knocking, and completely lost motive power on the roadway. Because the engine seized instantly, the vehicle experienced a sudden loss of power steering and power braking while managing the extreme weight of a trailer. This combination created a severe and immediate safety hazard, forcing me to maneuver a heavy, unpowered truck and trailer combination through active traffic to the shoulder without full steering or brake control, putting my life, my passengers' lives, and the safety of surrounding motorists at extreme risk. My dad read the codes before we took it to my mechanics and the only code I can remember is P0016. I took it and dropped it off at my local mechanics on 6/28/26. This is what my mechanic said: No Start-Truck came in not running. Had timing codes. I believe the crank bearing failed causing the engine to lose oil pressure. With the sudden loss of oil pressure, the timing chain tensioner slacked and caused the cam/crank to go out of time. Drained engine oil and found bearing material. We also cut oil filter open and found more bearing material. The timing cover was removed and verified the cam timing was off. In conclusion the engine has failed and will need full replacement. This is the exact failure mechanism under active the federal safety agency Investigation EA26005.
1. I am being told that the high-pressure fuel pump (HPFP) catastrophically seized and locked up internally while driving. Because the HPFP on the 3.0L Duramax (LM2) engine is directly driven by the engine's timing system, this sudden mechanical seizure instantly destroyed the engine timing gears and snapped/skipped the timing chain. The failed components are currently intact inside the vehicle and are fully available for inspection upon request at Ron's Smith GMC in Merced, CA. 2. The failure occurred on busy Labor Day (XXX) while our family of [XXX] was traveling back home at 70 mph on a major highway. The truck violently shook, instantly lost all engine power, and forced the vehicle into a dangerous limp-mode state before completely stalling in live highway traffic at night around 10:45 pm. This sudden loss of propulsion at high speed severely compromised our ability to safely navigate out of the way of fast-moving highway traffic, creating an immediate & extreme risk of a high-speed rear-end collision. At times hazard lights didn't work causing family panic & screaming as truck shook with passing traffic. 3. The problem has been officially confirmed by Ron Smith GMC in Merced, CA. Their service department diagnosed the issue, confirming that the high-pressure fuel pump had locked up and subsequently destroyed the timing belt/chain & engine gears. 4. The vehicle and its failed components have only been inspected by technicians at the Ron Smith GMC dealership service department. No police, insurance representatives, or outside third parties have inspected the vehicle yet. 5. I had been extremely happy with my truck and there were absolutely no warning lamps, dashboard messages, or driving symptoms prior to the failure. The truck was operating perfectly normally under cruise until the exact moment of the failure, at which point a "Reduced Engine Power" warning flashed on the dashboard simultaneously with the mechanical lock-up, shaking, and immediate stall. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF
Received Re-Call for Engine Failure! Dealer replaced Engine Oil and Oil Cap @ 85,544 Miles. I read of the Re-call prior to the notice and I waited for it to come. After I received it and the Dealer made the changes, it made me afraid to leave town using my truck for fear of a breakdown on the Freeway. I use a Walker, so if I broke down and I was in the left lane and lost all power it would be very dangerous for me to get to the right side of the road! The truck started using excessive Oil after they changed the oil. I replaced four (4) quarts of oil @ 2526 miles! Speedometer reading 88070 miles.
1. I am being told that the high-pressure fuel pump (HPFP) catastrophically seized and locked up internally while driving. Because the HPFP on the 3.0L Duramax (LM2) engine is directly driven by the engine's timing system, this sudden mechanical seizure instantly destroyed the engine timing gears and snapped/skipped the timing chain. The failed components are currently intact inside the vehicle and are fully available for inspection upon request at Ron’s Smith GMC in Merced, CA. 2. The failure occurred on busy Labor Day (XXX) while our family of [XXX] was traveling back home at 70 mph on a major highway. The truck violently shook, instantly lost all engine power, and forced the vehicle into a dangerous limp-mode state before completely stalling in live highway traffic at night around 10:45 pm. This sudden loss of propulsion at high speed severely compromised our ability to safely navigate out of the way of fast-moving highway traffic, creating an immediate & extreme risk of a high-speed rear-end collision. At times hazard lights didn’t work causing family panic & screaming as truck shook with passing traffic. 3. The problem has been officially confirmed by Ron Smith GMC in Merced, CA. Their service department diagnosed the issue, confirming that the high-pressure fuel pump had locked up and subsequently destroyed the timing belt/chain and engine gears. 4. The vehicle and its failed components have only been inspected by technicians at the Ron Smith GMC dealership service department. No police, insurance representatives, or outside third parties have inspected the vehicle yet. 5. I had been extremely happy with my truck and there were absolutely no warning lamps, dashboard messages, or driving symptoms prior to the failure. The truck was operating perfectly normally under cruise until the exact moment of the failure, at which point a "Reduced Engine Power" warning flashed on the dashboard simultaneously with the mechanical lock-up, shaking, and immediate stall. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF
On [XXX], my vehicle suffered a complete loss of propulsion on the highway, displaying fault codes P0324 and P0016. The vehicle was taken to Boyd's Tar Heel Chevrolet in Roxboro, NC, where the engine block was replaced under the official GM 6.2L engine safety recall.The truck was delivered back to me, and on the very first day I drove it—only 28 miles from my house—it suffered a secondary catastrophic loss of propulsion on the highway on [XXX]. The check engine light began flashing violently, indicating an immediate catalyst-damaging safety hazard, and the vehicle displayed fault code P0307 (Cylinder 7 Misfire).The dealership explicitly instructed me to stop driving the vehicle immediately, authorized the recovery, and told me to bill the tow directly to them. After towing the vehicle back to their facility, Boyd's Tar Heel Chevrolet reversed their position. They are now attempting to hold me financially responsible for the towing fees, along with spark plugs, wiring, and fuel injector services, claiming the failure is due to routine maintenance.This represents a severe highway safety hazard, a direct failure of the manufacturer's official recall remedy, and potential dealer misconduct to avoid liability under the active the federal safety agency Engineering Analysis EA26005 for post-recall 6.2L engine failures. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
Service bulletins that may apply
- Condition where the connecting rod and/or crankshaft engine components in these vehicles may have...
- Under Field Actions N252494000, N252494001, the service procedure includes performing a PICO test on...
- Condition that could
- This technical bulletin provides a procedure to replace the camshaft actuator magnet to correct customer...
- This informational bulletin advises the technician of a part number change for long block engines used in...
- This service bulletin provides information on replacing the intake manifold when the engine is replaced...
- This bulletin advises the tech to inspect deeper into what may be to main
- The service bulletin advises the tech of a normal transmission shift condition and the delay in throttle...
Related recalls
Engine and engine cooling: engine: hard parts internal/mechanical
- What is wrong
- General Motors LLC (GM) is recalling certain 2021-2024 Cadillac Escalade and Escalade ESV, Chevrolet Silverado 1500, Suburban, and Tahoe, GMC Sierra 1500, Yukon, and Yukon XL vehicles equipped with a 6.2L V8 gas engine. The connecting rod and/or crankshaft engine components may have manufacturing defects that can lead to engine damage and engine failure.
- Risk
- Engine failure increases the risk of a crash.
- Remedy
- Dealers will inspect the engine, and as necessary, repair or replace the engine. For vehicles that pass inspection, dealers will add higher viscosity oil, install 6 oil fill cap, replace the oil filter, and update the owner's manual. Repairs will be performed free of charge. Owner notification letters were mailed June 18, 2025. Owners may contact Cadillac customer service at 1‑800‑333‑4223, Chevrolet customer service at 1‑800‑222‑1020, or GMC customer service at 1‑800‑462‑8782. GM's number for this recall is N252494000.
Recall number 25V274000 · Recall details
Questions about the 2021 GMC Sierra 1500 engine failure
Is engine failure a common problem on the 2021 GMC Sierra 1500?
115 of 603 owner complaints about the 2021 GMC Sierra 1500 (19%) mention engine failure. The model year with the most reports is 2019.
How much does it cost to fix engine failure on the 2021 GMC Sierra 1500?
Owners who mentioned a price put the repair at about $9,300 (median of 7 complaints that include a dollar amount). Costs vary with mileage, warranty and where the work is done.
Is there a recall or service bulletin for this on the 2021 GMC Sierra 1500?
There is 1 recall and 320 service bulletins for the same area of the car. Check them below with your VIN.
Other symptoms on the 2021 GMC Sierra 1500
Check engine light 111Loss of power 65Knocking 56Misfire 25Oil consumption 21Stalling 21Shudder 19Won't shift 19Jerking 18Won't start 17Hesitation 15Transmission failure 15Harsh shifting 13Overheating 11Warning lights 11Fire or smoke 10Grinding brakes 9Slipping 8Adaptive cruise 7Power steering loss 7Steering lock-up 7Headlights 6Screen failure 6Ball joint 5Fuel pump 5
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