2,108 of the
11,357 complaints filed about the GMC Sierra 1500
are about the engine —
19% of everything owners reported.
The worst model year for it is 2021.
At approximately 14,000 miles, the 6.2L V8 engine experienced a major failure due to a spun main bearing, which resulted in the complete replacement of the engine. The vehicle remained at the dealership for more than 60 days while the repair was completed. After receiving the vehicle back, it operated without any significant issues until approximately 30,000 miles, when the engine experienced another major failure. This second failure was attributed to the lifters, and the engine required substantial repairs and ultimately had to be rebuilt. Having two major engine failures before reaching 30,000 miles—first requiring a complete engine replacement and then requiring the replacement engine to be rebuilt—has raised serious concerns regarding the vehicle’s long-term reliability and durability.
NHTSA complaint #11758441 — an unverified report by a vehicle owner.
Vehicle was traveling at 65 mph on a busy highway when vehicle engine stopped. A message on the dash appeared indicating to driver to shift to neutral and try to restart engine. As vehicle was quickly loosing speed it was decided to coast to the side of road to avoid someone running into vehicle causing multiple cars to crash. After stopping vehicle, an attempt was made to start vehicle. Engine would not turn over. Vehicle was towed to dealership. The following day I was informed that the engine needed replacement.
NHTSA complaint #11758326 — an unverified report by a vehicle owner.
Vehicle: 2026 GMC Sierra 1500 AT4 (3.0L LZ0 Duramax Diesel) Current Mileage: ~16,500 miles Check Engine Light Status: NO Check Engine Light active Description of Incident & Symptoms: •Interstate Incident: While driving at highway speeds, a severe drivetrain vibration occurred (felt like a rear wheel weight flew off). •Dashboard Warnings: Within 5 minutes, intermittent "Traction Control" and "Forward Collision Warning" alerts appeared on the dash, accompanied by a sudden drop in engine power. •Engine Noise & Idle: Once safely pulled over, the engine exhibited a loud mechanical knock and a very rough, unstable idle. •Extended Crank: After shutting the engine off and waiting a few minutes, restarting the truck took roughly twice as long as normal (long crank/delayed start)
NHTSA complaint #11758123 — an unverified report by a vehicle owner.
On XXX at approximately 3:00 p.m., I was driving on the highway in [XXX], at approximately 65 mph when my truck suddenly displayed a warning stating that all oil pressure had been lost and that the engine needed to be shut off immediately. Within roughly seven seconds of seeing and comprehending the warning, I attempted to safely shut down the engine. Before I could do so, the engine seized while the truck was still traveling at highway speed.The engine failure caused an immediate loss of power steering and power-assisted braking, leaving me with limited control as the truck coasted at highway speed. This was an extremely dangerous situation that could have resulted in a serious accident, injury, or loss of life. The truck was towed to a repair facility, where technicians confirmed that the engine had seized and recommended replacing the long block. A new GM Genuine Parts engine was installed, and the repairs were completed on XXX. Today, XXX, the replacement engine has approximately 40,000 miles on it. I recently began hearing a ticking noise followed by knocking, and the engine nearly stalled while idling. I immediately checked the oil and confirmed that oil was present on the dipstick. I have consistently maintained the vehicle and completed every oil change at intervals of 5,000 miles or fewer. I returned the truck to the same repair facility that installed the replacement engine and was immediately informed that the truck requires yet another engine replacement. This is now the second 6.2L L87 engine that has failed in this vehicle. Two catastrophic engine failures—one involving a replacement GM Genuine Parts engine after only approximately 40,000 miles—are completely unacceptable. The first failure created a severe highway safety hazard, and the failure of the replacement engine raises serious concerns about the reliability and safety of these engines. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
NHTSA complaint #11758114 — an unverified report by a vehicle owner.
Engine seized on June29th while driving on I 64 . (6.2 L87) due to oil line failure. Engine replaced on July 18th, 2026. New engine started leaking oil from camshaft and gasket on August 10th 2026, back in GMC Shop on August12th 2026 for repairs, still waiting parts today. Sudden failure on road in traffic Inspected by GMC Southpoint. No indication prior to failure and shut down completely. Could not do anything to move vehicle out the road.
NHTSA complaint #11757364 — an unverified report by a vehicle owner.
My 2019 GMC Sierra 1500 AT4 equipped with the 6.2L engine experienced an internal engine/lifter failure. The vehicle was inspected by an authorized GMC dealership. The dealership documented damaged lifters, including rough edges and visible signs of friction, and advised that the camshafts on these vehicles can also have issues. I was provided estimates for both a lifter repair and complete engine replacement. Due to the possibility of additional internal engine/camshaft damage and the risk of having to repeat the lifter repair, complete engine replacement was recommended. The dealership is replacing the engine with a GM remanufactured engine, part #19420611, carrying a 3-year/100,000-mile warranty. The customer-paid repair is approximately $9,400 plus applicable taxes and shop charges because my 2019 vehicle/VIN is not currently included in the existing L87 engine recall. I am submitting this complaint because NHTSA is currently investigating failures involving 6.2L L87-equipped vehicles outside the existing recall population. I believe this failure should be documented and considered as part of the investigation into whether the affected vehicle population should be expanded. I have requested the dealership provide the technician's complete diagnosis and documented cause of failure and can provide additional information when received.
NHTSA complaint #11757455 — an unverified report by a vehicle owner.
The engine shuts off while slowing down. It cuts off cleanly and the entire dash lights up and the transmission shifts to neutral. The driver display says to put the truck in park and hit the start button. After you do this the truck runs fine for about 2k-3k miles and does it again. I has done this 5 times within 10k miles. The dealer says nothing is wrong with the truck because the computer doesn't record any codes. This happens regardless of whether the auto stop/start feature is on or off.
NHTSA complaint #11757365 — an unverified report by a vehicle owner.
I was driving north/east on [XXX] just outside of [XXX]. After accelerating to give another driver room to move out of his lane that was ending, I lost propulsion/power. The Sierra went into Neutral and told me something like "Press Start to resume". I had to immediately get off the interstate as I was rapidly losing speed. I was able to pull over to the shoulder of the interstate on the right, just before exit 2. After getting the vehicle parked, I was never able to restart the vehicle. The motor would not turn over. The display screens kept cycling between a blank display and a display that looked like the vehicle was on but the engine never turned on. When I tried to start the car, I got a message of "conditions not correct for shift". We could not even get the vehicle into Neutral. I used OnStar to get State Patrol to show up and put lights behind us for safety. OnStar should have a recording of this call. This was on Saturday XXX in the ballpark of 2:30 pm central time. I would imagine the officer also filed a report, but I did not get it. The vehicle was towed to Billion GMC in Iowa City. Billion GMC said their initial suspicion is the 6.2L motor failed / locked up on us as this is know issue that is subject of a class action lawsuit. These vehicles ARE NOT SAFE to be on the highway, someone is going to get seriously injured, please do everything you can to get these 6.2L engines off the road before someone dies. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
NHTSA complaint #11757264 — an unverified report by a vehicle owner.
Sudden catastrophic engine failure occurred at 7400 miles, 2026 GMC Sierra1500 Denali with 6.2L engine. Driver and 3 children in vehicle headed to school when engine suddenly failed while driving on the roadway. No warning or vehicle symptoms prior. We were told the truck needs a total engine replacement- on a brand new vehicle. It has been nearly 9 weeks with no resolution or repair from GM. The truck was towed to the GM dealership it was purchased from on June 18th and it remains sitting in their service department lot with no timeline for repair or replacement.
NHTSA complaint #11757259 — an unverified report by a vehicle owner.
There was a catastrophic internal engine failure, due to cam/lifter/bearing issues. This caused the timing chain and tensioner to jump and the engine to be out of alignment. This caused the valves to all be bent as a result. I believe that this has been an issue for longer than what GM has originally recalled for, and I am submitting this complaint because I read that there is an active investigation into this.
NHTSA complaint #11756910 — an unverified report by a vehicle owner.
The contact owns a 2026 GMC Sierra 1500. The contact stated that while driving 70 MPH and depressing the accelerator pedal, the vehicle started decelerating unintendedly. The message “Engine Power Reduced” was displayed. A dealer was contacted. The vehicle was taken to a dealer where it was diagnosed and determined that the engine needed to be replaced. The vehicle was repaired. The manufacturer was notified of the failure and opened a case. The approximate failure mileage was 6,028.
NHTSA complaint #11757030 — an unverified report by a vehicle owner.
At approximately 85,000 miles, the engine in my 2019 GMC Sierra 1500 seized. The vehicle was parked when it occurred. This created a safety risk because an engine seizure can cause sudden loss of propulsion in traffic. Before the failure, I didn't notice anything that would raise any alarms. The problem was inspected and confirmed by a GMC dealer, which diagnosed the condition as an engine seizure. The failed engine is not available for inspection. I am not aware of the precise internal cause beyond the dealer’s diagnosis.
NHTSA complaint #11756621 — an unverified report by a vehicle owner.
At approximately 85,000 miles, the engine in my 2019 GMC Sierra 1500 seized. The vehicle was parked when it occurred. Inability to start. This created a safety risk because an engine seizure can cause sudden loss of propulsion in traffic. Before the failure, I did not notice any red flags. The problem was inspected and confirmed by a GMC dealer, which diagnosed the condition as an engine seizure. The failed engine is not available for inspection. I am not aware of the precise internal cause beyond the dealer’s diagnosis.
NHTSA complaint #11756622 — an unverified report by a vehicle owner.
2021 6.2L GMC Sierra Denali. Has the L87 engine that is recalled but yet my truck doesn’t fall under the recall although the recall is for 2021-2024 engines. Everything that the engine recall states is the issue with my truck, I have service report from dealership stating that there is wear/breakage of cam shaft/crank shaft amongst other things including cylinder 3 and 5 misfiring , bearings broken , filings in the oil , banging in the engine and safety lights on. My local GMC dealership recommended that the only acceptable action was to replace the engine at my cost of course. This is unacceptable of a supposed reputable large corporation not caring about the “little guy”. The truck only has 136000 kms on it and I was only going 60 km/hr when this happened. Please help as I feel GM knows this engine is faulty but somehow has managed to escape a recall on my vin number
NHTSA complaint #11756392 — an unverified report by a vehicle owner.
The contact owns a 2026 GMC Sierra 1500. The contact stated that while driving 45 MPH and depressing the accelerator pedal, the vehicle slowed down unexpectedly. The vehicle then lost power while stopped at a traffic light. No warning light was illuminated. The vehicle was turned off and restarted, and the vehicle operated as intended. The vehicle was taken to the dealer, where it was diagnosed and determined that there were metal shavings inside the oil pan and the engine needed to be replaced. The engine was replaced twice. The manufacturer was not notified of the failure. The approximate failure mileage was 3,202.
NHTSA complaint #11756457 — an unverified report by a vehicle owner.
The vehicle stopped dead in traffic and would not restart. No warning lights. This is a huge safety hazard. Had to be towed to a dealership. The dealership and other diesel shops said the issue is a known catastrophic CP4 fuel pump failure. The fuel pump shreds and metal shavings are found throughout the fuel system. Requires a full fuel system replacement...quotes have been obtained from GM dealership and local diesel mechanics, ranged from $15,000-$17,000. There is a known fix and could have been solved by replacing the fuel pump with an alternative one, without putting us in a dangerous situation. There is also a settled class action lawsuit directly associated to this fuel pump and issue, however the vehicle was purchased in GA and therefore not included. Based on the VIN the truck would be included if sold within a qualifying state. GM corporate and dealers know about this problem and the safety risk, but are not even suggesting the fuel pump conversation as a repair. They are putting customers in dangerous situations and leaving them with high bills.
NHTSA complaint #11756191 — an unverified report by a vehicle owner.
I was driving doing about 60 mph. All of a sudden the engine stopped and the truck just coasted. I was able to find a safe spot on the side of the road and pull over. Called a tow truck and had it taken to the GM dealership nearby. The trucks engine was just fixed in October of 2025 for the camshaft and lifter rods. It’s currently in the shop and I’m waiting for the diagnostics.
NHTSA complaint #11756301 — an unverified report by a vehicle owner.
On [XXX] I was driving my 2024 GMC Sierra 1500 Vin # [XXX] on a major highway in Houston when without warning the engine shut off, stranding me in the middle of busy traffic. I was able to get to the shoulder and restart the truck, but no warning lights came on so I continued on my drive when approximately 20 minutes later, while still on a busy freeway, the engine shut off again. I was able to restart the truck and within another 15 minutes the check engine light appeared, the engine lost power and started making a loud rattling noise. Roughly 2 minutes later, as I was attempting to pull over to the shoulder and safety, the truck shut off and would not restart. This was the 3rd time for it to stall out on a busy freeway which was very dangerous for myself and the other drivers. I contacted the local Chevy dealership and they sent a tow truck out to tow the truck back to their dealership service center. I was later contacted by a service advisor that said they found a code P0016. He informed me that the engine would need to be replaced. As of today 8/11/26, they are still waiting on backordered parts to arrive before they can even start on any repairs. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
NHTSA complaint #11756357 — an unverified report by a vehicle owner.