2023 GMC Sierra 1500 engine problems

ENGINE

The contact owns a 2023 GMC Sierra 1500. The contact stated that while driving 65 MPH, the engine made a clunking, knocking, and tapping sound. The engine was driving on seven of the eight cylinders. The contact slowed down and pulled over. The engine warning light was illuminated. The vehicle was taken to the local dealer and was diagnosed with a detached valve. The vehicle was repaired under an extended warranty. The dealer informed the contact that the failure might recur. The failure mileage was approximately 12,998.

NHTSA complaint #11763017 — an unverified report by a vehicle owner.

ENGINE

A GM warranty engine replacement was performed at Heyward Allen GMC in [XXX] on XXX at 70,415 miles. We purchase the vehicle on XXX with 73,904 miles and after driving for a month started having multiple malfunction indicator lights displaying, and experienced a no start condition. We took the vehicle to the Don Ledford GMC dealer in [XXX], and they performed a high level inspection. They found missing mounting brackets, loose wiring harness wires, broken and missing bolts. Issues all related to an engine replacement procedure. Deeming the vehicle unsafe to operate. The origin dealer that was paid through GMC to replace the engine is now refusing any responsibility for resolving these issues. Technicians have video evidence of the workmanship issues, documenting the sub- par repair work performed during the engine change. The vehicle now sits at the Don Ledford GMC dealer awaiting an estimated $4400 repair, before the vehicle is safe to operate on the road. The vehicle has been at the Don ledford dealer since XXX, and is still there today, XXX. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA complaint #11763072 — an unverified report by a vehicle owner.

ENGINE

The 6.2 engine in my truck failed while driving and it has been determine that I need a new motor. This motor was on the recall list. I brought it in for the PICO recall test in October we 2025 and it passed. They then changed the oil for a much more expensive 0w40. The engine failed in August leaving me stranded on side of the highway. It has been at the dealership since August 7th. There is no eta on when the new motor and parts will be available because I’m being told that some parts are on back order. I have looked into trading it in and the value of this truck due to the 6.2 engine recall is significantly lower that it should be. It’s half of what I paid for it 3 years ago. I incurred towing fees and Uber fees. I am no without a truck to tow with.

NHTSA complaint #11762905 — an unverified report by a vehicle owner.

ENGINE

I am reporting a serious safety concern involving a 2023 GMC Sierra 1500 Denali, 6.2L L87 V8, VIN [XXX]. This vehicle has now experienced two catastrophic powertrain failures at very low mileage. The first catastrophic engine failure occurred at approximately 23,696 miles. The vehicle was taken to a GMC dealer, where the repair documentation states that the engine had suffered significant internal damage, including damage to the #3 connecting rod, a missing connecting-rod bearing, bearing material throughout the engine, and a scored crankshaft. The dealer determined that the engine was seized and required replacement. GM replaced the engine under warranty with GM engine assembly part number 12740076. The vehicle has now experienced a second catastrophic failure. On [XXX], while traveling approximately 40 mph, experienced grinding, lurching, and knocking, followed by a complete loss of propulsion. The truck would no longer move and had to be towed to a GMC dealer. At the time of the incident, no warning lights or warning messages were observed. The transmission is also suspected to have failed, although the exact cause and extent of the transmission failure have not yet been determined by the dealer. I understand that NHTSA is currently investigating failures involving GM 6.2L L87 engines, including failures occurring after previous recall remedies and engine replacements. I am therefore requesting that this incident be included in NHTSA’s investigation and considered when evaluating the effectiveness of the existing recall remedy and the safety of replacement L87 engines. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA complaint #11761755 — an unverified report by a vehicle owner.

ENGINE

While driving, my 2023 GMC Sierra with the L87 6.2L engine experienced a sudden, complete, catastrophic loss of engine power. There were no warning lights or messages prior to the failure. This was a one-time event, but it left the truck inoperable and I have been without the vehicle since it happened. The vehicle had recently passed applicable recall checks and had a routine oil change performed, so it was properly maintained leading up to the failure. A sudden loss of engine power while driving poses a serious safety risk, including the possibility of a collision if it happens in traffic or at highway speed. It is unknown whether a dealer has confirmed the root cause, as the vehicle has been out of service since the incident.

NHTSA complaint #11761354 — an unverified report by a vehicle owner.

ENGINE

I am reaching out to NHTSA due to a vehicle that I believe will get me and/or my family in a major accident and cause serious injury or death. The vehicle that I had purchased in 07/08/2025 had a clean history report and was bought at 54,587 miles. It started having issues 8,563 miles later (odometer reading 63,150 ) on a trip that was 400 miles round trip. I was driving the vehicle on a highway at 65 mph and i felt a knocking vibration in the pedal it was not long before i could even pull over when the engine throttle had completely lost power causing the vehicle to almost come to a complete stop immediately having to steer onto the shoulder. after failing with no check engine light or warning present during the use of the vehicle on the road. it was giving off high temp/engine overheating with the engine making a continuous knocking sound in the engine. It eventually seized to work completely not being able to shift into neutral to push, and had to get it towed to the dealership 204 miles away. GM had advised the dealership to replace the whole engine which they did, and that second engine had given out 678 miles later (odometer reading 63,828.) I am now on my THIRD engine and i cannot trust or rely this vehicle for saftey or transporation. i have reached out to GM to file a claim and attempt to adress this issue to try and come to a resolution, however they denied my claim and have said that i am not "eligible" for a buyback program. I am considering getting legal attorney this is very frustrating to say the least GM is a terrible manufacturer for this issue

NHTSA complaint #11761466 — an unverified report by a vehicle owner.

ENGINE

The Engine made a noise and it seems to me that this engine will loose power and leave me in a situation that could cause an accident or breakdown in the middle of a bad situation. I don't trust this truck and its engine and i refuse to drive it now.

NHTSA complaint #11760713 — an unverified report by a vehicle owner.

ENGINE

My wife and I were driving on the highway going slightly uphill. I pushed the pedal a bit because the power wasn't keeping speed. It continues to not maintain so pushed throttle further and the truck stalled. We traversed 3 lanes to get to the shoulder. When I stoped I tried to restart but the car wouldn't turn over but all electrical were working. We were on the shoulder for over and hour on a main highway. We had aaa tow it to the dealership where they confirmed the engine was seized and will be ordering parts. The car is still available upon request. Our safety was at risk from loosing power on the interstate and sitting on the shoulder is very dangerous. I didn't receive any warning lights prior to this occuring. The truck did undergo the peko test and passed and added new oil viscosity. It had roughly 55k miles on it. Always changed the oil before it hit 0% oil life as told by dealerships.

NHTSA complaint #11760817 — an unverified report by a vehicle owner.

ENGINE

1 - The Engine or something electrical, possibly the ECM, failed or malfunctioned, and yes, it is available for inspection. 2 - The vehicle lost power, reduced speed, was hard to steer, and I couldn't put the hazard lights on; this occurred twice while driving on the highway, once I was driving at approx 75 mph. The results could have been catastrophic not only to myself but to others on the road. These two events are not the only times the truck did this. 3 - No. 4 - No. I filed a claim with GM, but it has been approximately a month, and I've received no updates. 5 - No. Further: This event has occurred 6 times. I've taken it to the dealership three. They cannot duplicate the issue, so no repairs have been done. Apparently, approximately 100 codes come up, but they cannot diagnose the problem.

NHTSA complaint #11760654 — an unverified report by a vehicle owner.

ENGINE

13 unresolved problem codes relating to hard engine starting,rough engine running,vehicle initiating safe mode operation, upon a highway trip. P0016 engine code detected and Onstar messaged for immediate service. No resolution at dealership , after resetting codes an additional 9 are active / pending at 2nd dealership visit. Abnormal engine operation since , dealership advises a hard failure has to occur before a resolution can be instituted. Similar advice from GMC direct phone call in help line.

NHTSA complaint #11760415 — an unverified report by a vehicle owner.

ENGINE

Truck went into limo mode while driving and required valve in transmission to be replaced. Went from driving normal speed to only being able to go about 15 miles and hour. Was repaired got the truck back and the next day was on the interstate in the fast lane and the truck again had speed issue reduced speed and had to coast off interstate. This time entire valve body had to be replaced. Have gotten truck back and still have hard shifting in the transmission at times. Engine was checked for recall and now I have to pay a much higher oil change price due to a GM issue. This was not a known cost when purchasing this truck.

NHTSA complaint #11760485 — an unverified report by a vehicle owner.

ENGINE

I am a Canadian owner of a 2023 GMC Sierra 1500 AT4 equipped with the 6.2L L87 engine. VIN: [XXX]. I purchased the vehicle new. I am reporting this because my experience appears directly relevant to NHTSA Engineering Analysis EA26005 concerning L87 engine failures after Recall 25V-274 remedies. The GM recall remedy/oil change was performed at 103,503 km (64,315 mi). At 130,695 km (81,210 mi), the original engine suffered a catastrophic failure and completely seized. The engine could not even be rotated manually at the crankshaft. GM replaced the complete engine. At 142,541 km (88,571 mi), only 11,846 km (7,361 mi) later, I returned for the first oil change on the replacement engine. I told the dealer that the vehicle was behaving abnormally, especially the transmission, which was shifting strangely. After inspection, the dealer determined that the replacement engine was beginning to seize. The increased resistance from the engine was causing the abnormal transmission behavior. The complete engine was replaced AGAIN. The vehicle now has 148,560 km (92,310 mi), meaning this second replacement/third engine has only about 6,019 km (3,740 mi). I am again noticing symptoms similar to those that occurred before the previous engine failure. I cannot confirm that this engine will fail, but after two previous engine failures, I am very concerned. This vehicle has therefore had two L87 engines: the original engine and one replacement. One replacement engine itself began seizing after less than 12,000 km. I believe these repeated failures after both the recall remedy and a complete engine replacement are directly relevant to EA26005 and the safety risk of sudden loss of propulsion. I have GM/dealer repair orders documenting the recall service and both engine replacements and can provide them upon request. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA complaint #11760512 — an unverified report by a vehicle owner.

ENGINE

Complete engine failure. Safety is was put at risk one engine lost propulsion on a bridge with no median. Truck towed to a GM dealer that inspected it and replace the engine. Check engine light and low oil pressure light came on approximately 30 seconds before the engine died.

NHTSA complaint #11759610 — an unverified report by a vehicle owner.

ENGINE AND ENGINE COOLING

The contact owns a 2023 GMC Sierra 1500. The contact stated that while driving approximately 40 MPH, the check engine warning light illuminated, and an oil message was displayed. The vehicle stalled and was unable to be restarted. The vehicle was towed to a dealer where it was diagnosed and determined that the engine needed to be replaced. The vehicle was repaired, but the failure reoccurred approximately two weeks later. The vehicle was taken to a different dealer but was not yet diagnosed. The manufacturer was notified of the failure. The failure mileage was 29,000.

NHTSA complaint #11759333 — an unverified report by a vehicle owner.

ENGINE

The contact owns a 2023 GMC Sierra 1500. The contact stated that while driving approximately 40 MPH, the check engine warning light illuminated, and an oil message was displayed. The vehicle stalled and was unable to be restarted. The vehicle was towed to a dealer where it was diagnosed and determined that the engine needed to be replaced. The vehicle was repaired, but the failure reoccurred approximately two weeks later. The vehicle was taken to a different dealer but was not yet diagnosed. The manufacturer was notified of the failure. The failure mileage was 29,000.

NHTSA complaint #11759333 — an unverified report by a vehicle owner.

ENGINE

During a family camping trip, our engine seized without warning — a failure directly tied to an active GMC recall. Despite this being a manufacturer defect, GMC roadside assistance refused to provide full support and informed us that we were responsible for towing our trailer home. This placed an unreasonable financial and logistical burden on us during an already distressing situation. To make situation worse when we brought the vehicle to O’Meara GMC for the recall repair Four months prior.They kept our truck for an entire week, only to inform us that their “solution” was to put heavier-weight oil in the engine. This is not a recall repair. It is not a fix. It is a temporary workaround that demonstrates clear incompetence and an inability or unwillingness to replace the motor as required under the recall. O’Meara GMC failed to perform the recall repair, failed to replace the engine, and failed to provide any meaningful resolution. Their actions have left us with a vehicle that is unsafe, unreliable, and not repaired according to GMC’s own recall standards.

NHTSA complaint #11759491 — an unverified report by a vehicle owner.

ENGINE

Sudden loss of propulsion while driving on I-75 with cruise control engaged. Vehicle began to decelerate. Pulled off onto emergency lane. Engine was idle-ing roughly. Would not increase rev when gas pedal pressed. Shut down. Tried one restart. Unsuccessful.

NHTSA complaint #11758858 — an unverified report by a vehicle owner.

ENGINE

Driving on I-75 with cruise control engages. Vehicle began decelerating. Pulled over onto emergency lane. Engine idled roughly. Shut down. Attempted one restart unsuccessfully.

NHTSA complaint #11758867 — an unverified report by a vehicle owner.

ENGINE

I, [XXX], am currently getting my engine replaced for the 1st time because of An engine failure. Engine completely shut down in the mountains while I had my 3 young kids ([XXX], [XXX] & [XXX] old) on our way to our vacation. 102 degrees outside no ac, no water for 4 hours until a tow truck finally came. The kids were scared for their life due to being on the side on the road, hungry with nothing to do but wait. Literally had just enough clearance to get on the side of road where vehicles drive-55-65 mph. Avenal, Ca to be exact. What’s the best way to get my money back? I do not want to continue to deal with these problems on the road with my little ones. The dealership is currently looking to replace my engine and waiting on parts. There has not been an official date I will get my vehicle back. Thank you in advance. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA complaint #11758888 — an unverified report by a vehicle owner.

ENGINE

I own a 2023 GMC Sierra 1500 Denali Ultimate equipped with the 6.2L L87 V8 engine. The vehicle previously experienced an engine failure that resulted in the complete replacement of the 6.2L engine by an authorized GMC dealership. The replacement engine was installed at approximately 76,316 miles. After approximately 1,000 miles of driving with the replacement engine, at approximately 77,354 miles, the vehicle displayed a check-engine/service warning and experienced abnormal transmission shifting. I returned the vehicle to the GMC dealership for diagnosis. The dealer documented DTC P0747, identified as “Transmission Control Solenoid Valve 1 Stuck On,” and recommended replacement of the transmission control valve body at a quoted cost of $2,665.85 plus tax. The dealership has stated that this transmission condition is unrelated to the recent engine replacement. However, because the condition appeared only approximately 1,000 miles after a complete engine replacement, I have asked General Motors to investigate whether the current failure could be associated with the previous engine failure, the engine replacement procedure, or other related vehicle systems. I have opened a case with General Motors Customer Assistance and have deferred the customer-paid valve-body repair while GM reviews the matter. I am submitting this complaint so NHTSA/ODI has a record that this vehicle experienced a major 6.2L L87 engine failure requiring complete engine replacement and then, approximately 1,000 miles after that replacement, developed a check-engine warning, abnormal transmission operation, DTC P0747, and a condition requiring replacement of the transmission control valve body. I can provide the engine-replacement repair order, current diagnostic documentation, mileage records, dealer repair estimate, and GM case information upon request.

NHTSA complaint #11758664 — an unverified report by a vehicle owner.

ENGINE

- vehicle started misfiring, ECM, valve timing code, throttle system code, data system, gateway, module,. Vehicle is available and currently at the GMC dealership for continued diagnostic. -this happened on the freeway and out of nowhere the vehicle started shaking, rough, losing power and acceleration, I had to cut someone off on the freeway just to get over to the right shoulder and turned off the vehicle called a tow truck and haven’t been able to use the vehicle since. Vehicle is unable to be driven due to safety issues of increased acceleration and loss of power, intense shaking. -the vehicle is at the dealership now, prior there was a diagnostic performed by a different dealer, and it has been confirmed. -the vehicle is at the GMC dealership now. -ECM check engine light came on prior to the vehicle misfiring and other codes coming up.

NHTSA complaint #11755389 — an unverified report by a vehicle owner.

ENGINE

Complete engine failure while driving on a highway. While cruise was set, the truck emitted a sound and sensation like we had run over something on the highway. Within a few minutes the engine started ticking. The cruise was disengaged which thru the truck into neutral. No dashboard sensors were illuminated. We were able to get off the highway but the truck would not restart. Truck was towed to nearest dealer who has confirmed engine failure.

NHTSA complaint #11752365 — an unverified report by a vehicle owner.

ENGINE

Driving down the interstate at 70 miles per hour, started losing power, engine light came on. Engine started making a loud banging noise as I pulled onto an exit.

NHTSA complaint #11751989 — an unverified report by a vehicle owner.

ENGINE AND ENGINE COOLING

The contact owns a 2023 GMC Sierra 1500. The contact stated that while operating the vehicle, there was an engine knock at start-up, and the engine intermittently hesitated and skipped. The vehicle was taken to the local dealer, who performed a PICO test on the engine, and the engine passed. Later, while hauling a trailer, there was a rattling sound coming from the engine. The vehicle was taken back to the dealer, who diagnosed the vehicle and determined that the engine needed to be replaced. The engine, radiator, and oil cooler were replaced, and the vehicle was repaired. The manufacturer was notified of the failure. The failure mileage was 17,000.

NHTSA complaint #11749583 — an unverified report by a vehicle owner.

ENGINE

Oct 2025 I took my truck into my local GMC dealer for 6.2 recall. I was told it passed the testing. 6/12/26 driving about 70mph on highway and lost all acceleration. Warning stating engine oil hot,/ pull over and idle engine. Already using 0w40 oil for approx 8momnths. Oil changed approx 3 wks before this incident. I was able to pull to the shoulder w/in 1/4 mile. While the truck was still moving about 3 mph it went into park and shut off. The vehicle would not turn back on. Oil level was full. For about $300 I was able to have the truck towed to a local dealer (about 2hrs from my home) and have my trailer towed off the highway. 6/15/26 I was notified by a local dealer that the engine was seized and that this was probably the recall issue. I contacted my local dealer who had my truck towed to their location. On 6/19/26 I was told by local dealer rep that they had ordered an engine for my truck and that I was third in line. On 6/26/26 I was informed by the dealer that he engine is on an indefinite backorder nationwide. On 6/30/26 I received a call from GM giving me a case number and getting contact info for my local dealer. I was advised that someone would contact me within 48 business hours. 7/3/26 I was contacted by my case advisor from GM. Still no idea when replacement engines might be available. I inquired about a buyback since I need a truck for work/personal life. I advised her that I had already cancelled one vacation (towing an RV...my loaner Buick Encore won't work) and would probably have to cancel another. I tried to explain that farming doesn't work well with the loaner either. I was told that another advisor would look into a buyback situation. On 7/8/26 I received a call from GM advising that my engine had shipped on 7/6/26 and to expect a call the following week with an update on completion.

NHTSA complaint #11749293 — an unverified report by a vehicle owner.

ENGINE

I was driving my family on the highway and my truck completely shut down. The screen flashed a warning and it slowly started decelerating. Thankfully I was able to make it to the shoulder of the road safely. Engine failure was a known safety issue with my model of truck, but I completed the L87 Engine Loss of Propulsion safety recall testing on 9/18/2025 and was assured my engine passed the testing and was not at risk for engine failure.

NHTSA complaint #11748693 — an unverified report by a vehicle owner.

ENGINE

While driving vehicle on state highway exit at approximately 55 mph a knocking noise started coming from engine then engine just died and would not restart. Engine was replaced under recall.

NHTSA complaint #11748009 — an unverified report by a vehicle owner.

ENGINE

Engine knocking. Engine being replaced under warranty due to premature bearing failure. Picotest was performed prior to my purchase with 12800 miles. 0w40 oil being used at the time of failure. At the dealer now getting the engine replaced.

NHTSA complaint #11747167 — an unverified report by a vehicle owner.

ENGINE

Traveling had an engine light come on. stopped at a dealer they inspected found multiple errors reset engine light and said continue home. when home bring into my dealer. Got home that night went to start truck, all kinds of errors started popping up on the dash, vehicle would not turn over at all. Had to call wrecker to have brought into shop. First issue could not put the truck into neutral at all, so they had to pull in park to put unto the bed of wrecker (that seems to be a very poor design of the truck). Brought truck into shop received a call two days later that it is fixed and working fine. Went to the shop asked what the problem was, told there is a ground strap under the truck that is like the main part to make sure everything works regarding electronics. The dealer has had to repair many of these ground straps, they are exposed to the elements and come loose I was told. They had two other GMC trucks in the shop with the same issue that day. the ground strap is exposed to the elements do not understand why this would not be covered just like a battery lead to stop from corroding and have to clean it or replace it. Not to mention there is no where in the service manual I can find about any maintenance that needs to be done with it. Appears to be a very bad design from the car manufacture.

NHTSA complaint #11747281 — an unverified report by a vehicle owner.

ENGINE

While traveling at highway speed during rush hour commute, the vehicle lost engine power and stalled. While coasting, I tried to restart the engine several times without success. Before coming to a stop, I attempted to get to the shoulder safely. Unfortunately, a portion of the vehicle was left partially in the lane and on the shoulder. Once I was completely stopped, I tried to put the electronic shift control into neutral so I could push the vehicle safely to the shoulder. The shifter would not allow me to shift into neutral and other override methods researched failed to work. I continued to try and restart the vehicle without success. I was in an unsafe position during rush hour commute for about 50 minutes until roadside assistance arrived and loaded and towed the vehicle. There was no warning of the issue prior to the incident. A code (P129F-Fuel Pump Driver Control Module Speed Signal Incorrect) was produced after the stall occurred via my GMC app. My vehicle was towed to my local dealership for service, but have not received the vehicle back at the time of reporting.

NHTSA complaint #11746738 — an unverified report by a vehicle owner.