2026 GMC Sierra 1500 engine problems

ENGINE

At just below 5,000 miles of use, my new 2026 GMC Sierra At4 (6.2L V8 engine) is currently undergoing a total engine replacement arising from traces of metal being detected in the oil filter. Although covered by GMC Warranty since it is essentially a brand-new vehicle, I wanted to report this issue as it is most likely part of the large GM recall pertaining to this L87 engine since I am concerned this is related to ongoing 6.2L L87 engine failure investigation. It is expected to be out for around 4-6 weeks with a new engine incoming and would want to be covered if the new engine fails in the future with any issues relating to this case.

NHTSA complaint #11764094 — an unverified report by a vehicle owner.

ENGINE

on Friday the 11th the vehicle quit running had to be towed and left me stranded in the middle of an intersection. This is a second vehicle from GM with the 6.2 L engine that has done this to me. The dealer says it’s catastrophic engine failure, and they’re gonna replace the engine. I was told that GM Edward repaired this issue but is still selling brand new trucks with this motor that has this failure, they can lead people stranded in very compromising positions.

NHTSA complaint #11764203 — an unverified report by a vehicle owner.

ENGINE

Was driving the vehicle and started making a loud knocking noise and had a loss of power.

NHTSA complaint #11763861 — an unverified report by a vehicle owner.

ENGINE

Rattling, knocking sound from the 6.2 ltr motor. Dealer verified engine failure, needs to be replace. Engine failed with only 4770 miles. Never made it to the first oil change.

NHTSA complaint #11762965 — an unverified report by a vehicle owner.

ENGINE

Complete engine failure. Had to get the engine replaced with only 2,700 miles on it. Back in the shop on 9/5 to fix the engine again.

NHTSA complaint #11762681 — an unverified report by a vehicle owner.

ENGINE

Three times this has happened. Most recently Pulling in drive and jumps out of drive to park with a jerk and stops.

NHTSA complaint #11762573 — an unverified report by a vehicle owner.

ENGINE

XXX Pulling into Mason Park - Truck Shot down while driving. Went into Park (immediate stop) 2 of my Kids were in the truck at the time. Restarted truck and loud Noises. Immediately backed into parking space shut down and towed. Sent to dealership XXX Called spoke co/ Mark. [XXX] had tech. look at truck. expressed My concerns and Should Never occurred @ 6788 miles. Expressed Something Needs done. Recommend contact GMc. - Call GMC, Crated a Case #XXX. Engine replaced after 2 months. No one checked the transmission or had explained why it went into park while in operation.Refused to look at any other concerns. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA complaint #11761659 — an unverified report by a vehicle owner.

ENGINE

We were told when we purchased our 2026 GMC Sierra 1500 that all the engine problems have been remedied. Purchased our new truck January 3, 2026 put 2001 miles on the truck went on June 29. The engine suddenly just stopped while driving on the highway. We were able to pull over unable to ever get it to start forced to have it towed to a nearby GMC dealer where it has been ever since were told it had to have a complete new engine put in we have corresponded with General motors on three different occasions we still sit with no offer as we did apply for a lemon law buyback but General Motors continues to sell these vehicles which is very deceptive and misleading as this situation was not remedied in any 25 or 26 models.

NHTSA complaint #11760716 — an unverified report by a vehicle owner.

ENGINE

Took ownership of this vehicle on XXX. 6.2 motor build date XXX at Tonawanda plant. Currently have 10,600 miles on vehicle. First and second oil changes at GMC facility T&T Coast Buick, GMC located in [XXX] First at 4,441 miles, oil part number 19420077. Second oil change at 8,379 miles, oil part number 19420077 This oil part number is for 5W-30. ACDelco bulk engine oil (Dexos1 Gen2 Full Synthetic 5W-30). The correct oil was not used. From what I have read this is a GM "oil trap" so if there is a problem with the motor GM can deny warranty coverage because the wrong oil was used. I have not adressed this with the dealership yet. If there is a 6.2 motor problem with my vehicle in the future am I going to be denied coverage? I am worried. I also have the extended warranty. Thank you. [XXX] [XXX] [XXX] [XXX] [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA complaint #11760724 — an unverified report by a vehicle owner.

ENGINE

While driving through city traffic at approximately 35 mph the truck engine made a quick loud noise and then immediately shutoff. The power steering went out and then I was unable to pull off the road completely as the engine would not start back up. This truck is a 2026 with 9,000 miles, 6.2L motor. After being towed to a GM Service facility it was determined that the motor had blown up on the truck. A vehicle shutting off while driving down the road is an extreme safety concern in my opinion.

NHTSA complaint #11760220 — an unverified report by a vehicle owner.

ENGINE

This truck has the GM L87 6.2L engine that is currently on recall for 2021- 2024 model years, but recently the NHTSA is looking into post engine replacement failures and 2025-26 model year issues. My engine at 7,000 miles failed for rod bearings. Same issues reported years ago and 100k engines ago. GM has not fixed the problem, its still happening.

NHTSA complaint #11759857 — an unverified report by a vehicle owner.

ENGINE

Bought the vehicle brand new at the end of april. 2 weeks later and at 557 miles, the engine had a lifter failure and needed to be replaced. One day after picking it up after the engine replacement, a fuel injector went bad and needed to be replaced. About 2 days ago, the check engine light lit up, and the GMC app said it was a code for the transmission system (popped on after attempting to remote start the vehicle, although the light did shut off on its own the next day after a software update on the vehicle)

NHTSA complaint #11759297 — an unverified report by a vehicle owner.

ENGINE

I bought the vehicle brand new in april 2026. On May 3rd, approximately 2 weeks after I bought it, I experienced a lifter failure that caused metal to get into the oil pan/engine and the engine needed to be replaced. About a month later after repairs were complete, I picked up my vehicle on a Friday night, and the very next morning, had issues again. Took it back to the dealer and a fuel injector went bad and needed to be replaced. I recently attempted to use the remote start feature and as soon as it fired up, the engine cut out. I went to start it again and the check engine light came on. My GMC app said the code was transmission related, although it cleared on its on the next morning after a software update.

NHTSA complaint #11759298 — an unverified report by a vehicle owner.

ENGINE

rocker arms replacement at 5,000 miles on my truck. Palm Harbor Tasca GMC

NHTSA complaint #11759354 — an unverified report by a vehicle owner.

ENGINE

What component or system failed or malfunctioned, and is it available for inspection upon request? The truck has lost power unexpectedly while driving, and lately I've also noticed some lag when I accelerate. The truck is available to be inspected. How was your safety or the safety of others put at risk? The truck suddenly lost power while I was driving and told me to restart the vehicle. Losing power unexpectedly almost caused me to get stuck in an intersection and could have caused an accident in a busy shopping center. Has the problem been reproduced or confirmed by a dealer or independent service center? No. I took it to the GMC dealership after the second time it happened, but they couldn't get it to do it again and said there were no codes showing. They told me to bring it back if it happens a third time. Has the vehicle or component been inspected by the manufacturer, police, insurance representatives or others? Yes. I took it to the GMC dealership to have it checked after the second power-loss issue happened. Were there any warning lamps, messages or other symptoms of the problem prior to the failure, and when did they first appear? When it lost power, the truck prompted me to restart the vehicle. I have also recently started noticing some lag when accelerating and starting the vehicle. There was no warning before it happened.

NHTSA complaint #11759373 — an unverified report by a vehicle owner.

ENGINE

Truck milage at the time of engine failure was 9,101. Well past the break in period for towing. We were towing a car trailer 2,000 pounds less the max towing capacity for the truck and going less than the posted speed limit. The truck was also in tow haul mode. The truck dash flashed oiled heating hot. We tried to pull over on the highway then the truck lost all power and overheated. Our trailer was not all the way off the highway, so a WY State Trooper pulled behind us and kept his lights flashing for 3 hours until a tow truck came. Truck could not be placed in neutral, so it had to be dragged onto the flat bed ramp of the tow truck. Truck was towed to the Gillette WY GMC dealership that same day. On Monday we were informed that the engine failed and needed to be totally replaced. The GM dealer cannot tell us how long it will take to get the new engine or how long we will be without the truck. This is the 6.2 V8 which GM assured buyer's of 2026 vehicles that the engine failures reported on previous year vehicles had been rectified on the new models. Less than 10,000 and the engine failed.

NHTSA complaint #11759533 — an unverified report by a vehicle owner.

ENGINE

Engine completely failed and had to be replaced

NHTSA complaint #11758996 — an unverified report by a vehicle owner.

ENGINE

This engine has used more than 2 quarts of oil since purchased in November of 2025. It has 12,000 miles on it. The exhaust pipes are covered in black soot from oil burn. It scares me to drive it, $87,000 retail vehicle worth about nothing with a bad engine. Terrible

NHTSA complaint #11758920 — an unverified report by a vehicle owner.

ENGINE

Catastrophic failure of engine while exiting the interstate.

NHTSA complaint #11758805 — an unverified report by a vehicle owner.

ENGINE

I bought a new GMC Sierra 1500 Denali with the 6.2L V8 engine in December of 2025. 7 months later, I was driving home from work. When the car started, it sounded a little louder, but not out of the ordinary. I started driving and got a strange rattle when I was getting on the highway at around 65MPH. I pulled off at the next exit and checked my fluids, checked under the car to see if anything was caught that was causing the rattle. All pressures and fluids were normal. I had Onstar run a system diagnostic. The diagnostic read normal. I got back on the highway and drove about 20 miles at 75mph. The rattling continued. 20 miles later, the check engine light came on. I had onstar run a diagnostic and came back stating “engine and transmission system problem” with two error codes. One code said “An issue has been detected in the Variable Valve Timing System adjust the timing of fuel delivery for more efficient engine operation”. The other code said “An issue has been detected in the Ignition System which oversees the timing and spark necessary to ignite fuel in your engine” Both error codes said to fix within one day. The GMC dealership was on the way home so I was going to stop there and see what they could do. I never made it to the dealer. About 2 minutes after the diagnostic, while doing 75mph on the highway, I hit the accelerator and the car did not speed up. The engine then shut off while I was in the left lane doing 75 mph. The electronics stayed on and the dash stated “press start to start engine.” I pulled over to the side of the highway and put the car in park and attempted to restart the engine. The engine never turned over again. I could not get the engine to start. I could not shift the car to neutral to have it rolled up on to the tow truck. My truck was towed to the GMC dealership and they are now replacing the engine under warranty. Will upload any maintenance paperwork once engine is replaced.

NHTSA complaint #11758612 — an unverified report by a vehicle owner.

ENGINE

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.

ENGINE

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.

ENGINE

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.

ENGINE

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.

ENGINE

Driving on the highway near Rockport, WA, when vehicle suddenly loss propulsion, engine light appeared, and vehicle went into transport mode enabled. Without causing an accident, I was able to pull to the side of the road. Once I put vehicle in park, it shut off and displayed, “Tranport Mode On. Vehicle would not start and was towed home. My son-in-law was able to disable transport mode, but vehicle still will not start. Will notify dealership on Monday.

NHTSA complaint #11755698 — an unverified report by a vehicle owner.

ENGINE

Driving on the highway near Rockport, WA, when vehicle suddenly loss propulsion, engine light appeared, and vehicle went into transport mode enabled. Without causing an accident, I was able to pull to the side of the road. Once I put vehicle in park, it shut off and displayed, “Tranport Mode On. Vehicle would not start and was towed home. My son-in-law was able to disable transport mode, but vehicle still will not start. Will notify dealership on Monday.

NHTSA complaint #11755699 — an unverified report by a vehicle owner.

ENGINE

2026 Denali, 6.2, failed after getting off express way while on my way for a fishing get away and pulling my boat. NO warning lights, noises, nothing. Came to a stop sign and at the last second slammed into park. Dash went black, 10 seconds later would come back on and try to start, then the dash goes black. Sheriff pulled up 20 or so minutes later and told my wife to get back into the vehicle as she was directing semis and other cars to go around. Towed to a chevy dealership 13 miles away. After Running tests on the truck, came up blown engine. 7600 miles. 5 hours later we left with a loaner and able to continue on with our plans. I do thank the dealership for their help and loaner. 23 business days later they delivered my truck to my house and returned in the loaner. After all my investigating on these engines, I will not be buying another one. Time for GM to invest some of their profits into finding the problem!

NHTSA complaint #11755712 — an unverified report by a vehicle owner.

ENGINE

I have a 2026 GMC Sierra 1500 with the 6.2L engine. I purchased it on [XXX]. On [XXX] with 13,000 miles on the truck the engine started making a bad noise from the lower end of the motor. I immediately took it to the dealer Randy Wise Buick GMC in Fenton Michigan. They diagnosed it as a spun bearing and had to replace the engine. I just got it back today August 7th 2026 INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA complaint #11755572 — an unverified report by a vehicle owner.

ENGINE

I was driving on 96 W. in slow traffic on the freeway when the vehicle put itself in neutral and shut off

NHTSA complaint #11754782 — an unverified report by a vehicle owner.

ENGINE

Engine died while driving at higher speed on interstate. Barely able to pull to emergency lane before truck stopped. No warning of any issues with it. Had towed to dealership. Dealership confirmed 6.2 engine was faulty. Engine replaced under warranty. Truck only had 1207 miles on it when engine died.

NHTSA complaint #11753938 — an unverified report by a vehicle owner.