general problems of the 2023 GMC Sierra 1500 - part 1

This vehicle has experienced repeated catastrophic engine and drivability failures since purchase and has now undergone four engine replacements under warranty. Despite these major repairs, the vehicle continues to experience dangerous shutdown/stalling conditions. The primary safety issue occurs while braking or coming to a stop. The engine will suddenly shut off unexpectedly, creating a serious traffic hazard and leaving the vehicle unable or difficult to restart. This has occurred multiple times and creates a dangerous situation in traffic and at intersections. The vehicle remains under manufacturer warranty, however the defect has not been successfully repaired despite extensive service attempts and multiple complete engine replacements. The condition substantially impairs the safety, reliability, and use of the vehicle. This vehicle was acquired through a fleet/lease arrangement for company use and was not purchased for resale. It is a light-duty 1500-series pickup with approximately 7,100–7,200 gvwr used as a company vehicle. Complete repair history, diagnostic records, warranty repairs, and engine replacement documentation can be obtained from: stevens GMC bristol, connecticut the vehicle has been repeatedly presented for repair and the defect remains unresolved. This appears to be a serious ongoing safety-related defect involving engine shutdown/stalling while braking or stopping.

On may 13. 2026 traveling southbound on i15 utah at 75 mph the engine stop and put the tranmisson in n and I move the truck to a stop. Then the truck shut down. I had the truck tow to the nearest GMC and was informed that the engine had sezed. I had recalled done to pervent engine failure.

Catastrophic internal engine failure on my 6. 2l engine. Several times vehicle was to gm gunn Buick GMC regarding power loss knocking noises. Received the run around that vehicle past all their initial inspection and test. They only replaced a valve lifter replacements bank 2 without further assessment of the engine or components. I took my vehicle to another shop to conduct a thorough inspection and they found broken metal from the piston/skirt and likely connecting rod damage inside the crankcase. Broken piston skirt/piston material • cylinder wall damage/scoring • metal debris throughout lower end • possible bent/broken connecting rod • potential crankshaft/journal damage from debris circulation • oil pickup area contaminated with metal lifter failure leading to dropped valve/ piston contact • rod bearing failure • oil starvation • spun bearing • piston failure/detonation advised gm gunn Buick and GMC of the secondary engine inspection by another shop. Manager told me it was my issue now and they wouldn’t replace my engine it wasn’t there problem. I had to pay out of pocket for a new engine replacement due to the negligence of gm and their agency lack of maintenance and customer care and service.

After completion of recall repair, changing oil weight from 0w20 to 0w40, I encountered loud squealing and knocking sounds from the engine bay. As catastrophic failure has been reported the vehicle was immediately taken to the closest gm dealership, southern Chevrolet of chesapeake, va.

I took the truck in for a recall they notified me and said it failed the test and there was metal in the oil and said it needed a new engine.

Start engine light came on while driving. The truck did a dead stop in the middle of the road. Tried to restart but nothing. A tow truck was called and the truck was dropped off at the local GMC dealer. The next day the dealer called me and told me I need a new engine. 39,000 miles.

I brought this truck brand new. Had issues the first couple days of purchase that was a quick fix, but as time went on things got worse. Truck always stalling out, engine has been replaced once already due to a recall and months after the first replacement, it stalled out on me again in the middle of the freeway and I just got a call from the dealership that it needs another new engine! how is this right! how is this safe! I could've lost my life on every occasion it has happened.

On April 1, 2026 at approximately 7pm the vehicle had a complete engine failure exiting an interstate. As I was slowing to exit the interstate the truck, without warning, lost power and locked up the rear wheels. I was able to safely exit onto the off ramp, but did partially block the off ramp for 45 minutes waiting on a tow truck. Once I came to a complete stop the dashboard began displaying numerous error codes, included "key missing, restart truck and shift to park, and start failure". The vehicle was part of the gm l87 engine recall but had previously passed the pico test and was deemed ok to drive. I had the vehicle towed to the closest GMC dealership where it was diagnosed as an engine failure and the engine was locked up. The vehicle has been at the GMC dealership since the night of April 1, 2026 with no date given as to when it will be fixed. The vehicle had displayed no signs of any problems prior to the engine failure on April 1, 2026.

Engine sudden loss of power. Wheels locked up and I skidded off the road.

Based on the critical recall and safety concerns for this known issue for the 6. 2 l87 engine failure I am highly concerned that it takes over 171 days to just get an appointment to look at this issue. This is further compounded by the fact I put approx 800-1000 miles a week on my truck and now am worried about having an accident or blowing my truck up.

Motor locked up on highway with heavy traffic trying to exit highway.

Our truck had just passed 60,000 miles when the engine seized. The recall procedure was completed in January, and the engine passed the test at that time. We were also using the recommended 0w?40 oil. Despite following all guidelines, the engine still failed. This shows that the procedure gm has outlined is not sufficient to determine whether an engine is actually in good condition.

My 2023 GMC sierra has 60,571 miles for a while now while driving the transmission slips and slams into gears. Recently driving with my kids in the car on highway going 70mph the back brakes locked up multiple times, so scary and dangerous while driving. I now currently have a code p-0747 in the system.

While driving home from phoenix on hwy 95, 30 miles out of tonopah on the way to reno engine propulsion and the complete engine failure occurred while driving at 75 mph. No warning at all. No cell service, had to use onstar to be our savior. Thank god they sent a tow truck, although my wife and I with 2 dogs had to wait 4 hours for the tow truck, while semi’s rolled by us going 80 mph. Dealer performed diagnostics on my truck and has to replace the engine due to engine failure. I had the recall completed in September with the new approved oil and cap. I know this is an ongoing problem with gm’s 6. 2 engine. Complete engine failure while driving at 75 mph. No engine warning sign. Screen went blank. I will no longer trust this truck or have any confidence in the truck once I get it back. I sure hope gm pays for this. This has caused me endless anxiety.

My vehicle is a GMC Sierra 1500 duramax diesel. The vehicle experienced a failure of the def (diesel exhaust fluid) system, which was diagnosed by the dealership as a failure of the def tank heater. The heater is integrated into the tank assembly, requiring full replacement of the def tank. As a result of this failure, the vehicle became unusable and has been out of service since March 3, 2026. The dealership confirmed that the required part is on national backorder with no confirmed availability date. This condition creates a significant reliability and potential safety concern. When the def system fails, the vehicle can enter a reduced power or speed-limited mode, which may occur during normal driving and could create unsafe conditions in traffic. Additionally, there appears to be a broader pattern of similar failures affecting other vehicles of the same type, combined with extended delays in obtaining replacement parts. The lack of parts availability results in extended periods where the vehicle cannot be safely or reliably operated.

Driving along a main road at 40-45 mph and coasting toward a traffic light, the engine stalled out. Traffic light turned green and the vehicle would not accelerate. There were no warnings, check engine lights, or sounds. I could not pull to the shoulder due to traffic and had to pull into a left hand turn lane. The truck would not restart. Electrical systems seemed fine. Engine would turn over but not start on multiple attempts. One attempt finally got it to start but it immediately stalled. I was stuck in a dangerous situation at a busy intersection and no way to move the vehicle. It has been towed to the dealership.

Engine with leas than 40,000 miles is consuming one (1) quat of oil every 2,000 miles. Gm dealership showed me the internal gm service update stating the accepted rate of oil consumption for engines uses in the vehicles referenced is 1qt per 2,000 miles. That may seem acceptable because gm put it in a notice to dealerships but I assure you the end consumer would never buy this engine if this was explained prior to purchasing. There is a reason new cars to not consume oil (at least not at a level you need to add oil between oil change intervals) at this rate. Long term wear and tear on the engine - note gm offered a warrantee covering 100,000 miles, which is nice but the problems will become more severe over time and miles. I consider this borderline criminal as it will surely cause engines to lock up.

Vehicle exhibited a sudden loss of power, dash screen stated a restart of the vehicle was needed. I was able to coast into a neighborhood upon attempting to restart the vehicle nothing would happen and it would not even attempt to turn over, proceeded to contact onstar for roadside assistance, vehicle taken to nearest GMC dealership where it was determined to have engine failure and a new engine under warranty will be installed.

Motor seized while driving.

On Saturday at approximately 5:30 p. M. , while driving on a two-lane city street with vehicles around me, my GMC sierra began malfunctioning. The gauges flickered, warning lights appeared, and a transmission warning activated. As I attempted to safely pull over, the vehicle began stuttering and then completely stalled in the middle of traffic. Cars swerved and honked to avoid hitting me. Fortunately, no collision occurred, but the situation was extremely dangerous and frightening. Aaa towed the vehicle to the GMC dealership. When I informed them of the incident, I received a text asking whether an over-the-air update had been performed prior to the stall. I confirmed the vehicle had received an update within the past three months. I was then told there is a bulletin stating that after an over-the-air update, the vehicle may suddenly lose communication with multiple modules and stall. The foreman indicated this was likely the cause and that they were consulting technical assistance. I asked when it is considered safe to drive a GMC vehicle following an update, as I was never warned that the vehicle could suddenly lose power and stall without notice. I was told they were investigating further. Yesterday, I was informed that engineering directed them to replace the ecm (engine control module) and the fuel pump control module, with the ecm expected to arrive next Wednesday. I have not been given a confirmed timeline for completion. This appears to be a serious and known issue within GMC, yet there has been no recall and no warning provided to consumers. I was unknowingly driving a vehicle susceptible to sudden and complete power loss. This failure placed my life, my family, and the safety of others at significant risk.

Engine lost all power while I was attempting to make a left turn at a very busy intersection. Dash kept saying “check battery”, jump pack did nothing. Engine wouldn’t start.

Incident summary: on 2/2/2026, my vehicle was serviced under safety recall 25v-274 at an authorized GMC dealership. The service technician performed the mandated diagnostic protocol (including the picoscope test) and informed me that the engine had "passed" inspection. No internal components were replaced; the remedy was limited to an oil change to a higher-viscosity oil (0w-40) and a new oil filler cap. The failure: approximately 48 hours after this "successful" recall remedy, the vehicle suffered a catastrophic engine failure while in operation. The engine failed entirely. The vehicle lost all propulsion while in motion, creating an immediate safety hazard for myself and other motorists. Diagnostic and risk: the failure has been confirmed by a GMC dealer, who subsequently performed a full engine and radiator replacement. In the 48-hour prior to failure, there were no warning lamps or symptoms; the vehicle had just been cleared by the manufacturer's own diagnostic tools as safe and free of defects. Systemic concern: this incident demonstrates that the current diagnostic protocol for recall 25v-274 is insufficient to identify terminal manufacturing defects in the connecting rods and crankshaft of the l87 6. 2l v8 engine. The "remedy" of higher-viscosity oil failed to prevent the exact catastrophic loss of propulsion the recall was intended to address. The replaced engine is available for inspection upon request by the NHTSA office of defects investigation.

On or about Tuesday, February 3, 2026 at 12:20 cst, at the Chevrolet dealership in libertyville, IL; I presented my 2023 GMC sierra to “manny” at said dealership due to the vehicle instructing me to do so because of dtc codes displayed indicating a failed def tank. I was told a technician would be able to diagnose the vehicle that afternoon. Makemodelyearvin Gmcsierra2023 [xxx] day 1: came and went with no contact from the service department as promised. Day 2: Wednesday, February 4 came with – again – no follow-up from the dealer. When I called I was told there were “no notes in the service order” and “the tech has gone home. ” day 3: Thursday morning “manny” called to tell me nothing was done and nothing could be done. I was told to “call gm” and complain about my problem. This is how gm treats its customers. This is how gm treats its repeat customers. This is how gm treats its customers who buy their extended warranties. Information redacted pursuant to the freedom of information act (foia), 5 u. S. C. 552(b)(6).

P1098 code for coolant control valve malfunction causing a radiator leak. Should be covered under warranty, but wyatt johnson in clarksville tennessee giving me the complete run around trying to get me to pay $3500 for a radiator replacement.

While traveling northbound on I?65 on Saturday, 1/31, the 6. 2l v8 engine in my 2023 GMC sierra at4 experienced a sudden and complete internal failure. My husband was driving and I was in the vehicle with him when the engine lost all power without any warning lights, messages, or prior symptoms. We were only able to coast into a very busy on?ramp merge lane before the truck died completely, leaving us stranded in an active traffic area for over two hours on one of the coldest days of the year, which created a significant safety risk for both of us and for other drivers. My truck was towed to the dealership. They inspected the vehicle, confirmed it was a full engine failure, and replaced the engine under warranty. The failed engine only had just over 37,000 miles on it at the time of the incident. Gm was notified through the dealer’s warranty process. No other agencies have inspected the vehicle.

My 2023 GMC sierra denali experienced a catastrophic engine failure even after receiving the official recall repair. The recall remedy did not prevent engine failure. This raises serious concerns about the effectiveness of the recall fix, especially given reports that NHTSA is evaluating this recall’s efficacy. I was stranded on a hill and this was a very dangerous situation.

The contact owns a 2023 GMC Sierra 1500. The contact stated that while driving uphill, the vehicle unexpectedly lost motive power. There was no warning light illuminated. The vehicle failed to restart and was towed to the dealer, where it was diagnosed, and determined that the engine block had failed and needed to be replaced. The vehicle was repaired. The contact stated that later, while driving at an undisclosed speed, the vehicle failed to shift into gear properly and jerked abnormally. There was no warning light illuminated. The vehicle was returned to the dealer and was diagnosed with transmission failure, requiring the pcm/tcm to be reprogrammed. The vehicle was repaired. The contact stated that while driving at an undisclosed speed, the check engine warning light illuminated, and the vehicle was taken back to the dealer, where it was diagnosed and determined that the fuel injector and coolant pump had failed and needed to be replaced. The vehicle was not repaired. The manufacturer was made aware of the failure, and a case was opened. The approximate failure mileage was 57,000.

2023 GMC sierra denali ultimate 1500 with 6. 2 v8 at highway speeds 65 mph the car lost propulsion and said it was in neutral. Car wouldn't shift back into drive. Barely made it off the highway without an accident. Car wouldn't restart. Car brought to dealership and was told it needs a new engine and I would be without my truck for a month. Car currently has 20,200 miles on it. Plus no loaner car. GMC has terrible customer service and sells a dangerous product.

I was driving on an overpass and suddenly loss propulsion in my vehicle. My vehicle stopped all of a sudden and while driving, leaving me stranded in the middle of the roadway blocking traffic. Numerous motorists stopped to give a hand but the vehicle would not switch gears from park, to neutral to even give me a hand moving the vehicle out of the roadway to the side/shoulder. Due to this issue, authorities were dispatched to my location to conduct traffic control and subsequently called in aide of a tow truck to safely move my vehicle to a better location. I used onstar in my vehicle and also spoke with a representative who notated the incident and I was advised that a tow truck would take approximately 90 mins to 2 hours to reach me. In this instance, that was too long of a wait for events going wrong with the vehicle itself and was subsequently transferred from the roadway to a GMC dealership, namely group 1 south on the gulf freeway. They are handling my repairs and have diagnosed that the engine needs to be completely replaced and are in the process of repairs. If any information is needed regarding status or repairs, please contact the dealership directly as I do not have any physical or written information on the status of my vehicle. Attached is the towing receipt.

My truck supposedly passed the initial recall for the 6. 2l gm engines. At this time they changed the oil and said the engine was fine! 5 months and one oil change (performed at the same gm dealership using the new recommended oil) my engine seized up while driving approximately 55 mph in rush hour traffic. The engine made a banging and clanging noise and lost power approximately 1/4 miles after the initial noise. This almost caused two accidents as the traffic had to come to a sudden stop, that’s engines are extremely dangerous to both the owners and the driving public on the highways alongside them. P the failure of the engine put me in a highly dangerous situation. This “oil” fix is not doing what gm is saying it will do. I was told yesterday that my vehicle will need a new engine and radiator. This is simply dangerous and it makes for a horrible financial situation with the truck already needing a new engine.

I had the truck inspected for recall n25249400 on August 11, 2025 with 24,610 miles. It passed the recall inspection and the dealer changed the oil to gm recall recommended oil. On January 18, 2026 with 28,275 miles, the engine seized while on a major highway. The truck lost all power and just turned off amd would not start or turn over. The vehicle was towed by the police due to the vehicle being in a dangerous spot in the middle of a lane on the highway whi h I had to pay out of pocket. January 19, 2026, the gm dealer confirmed that the truck needs a new engine due to the recall defect. They said that they had just ordered a new engine, but does olnot know hpw long ot will take to get and then install. The dealer is unable to provide a rental vehicle which means, I can't work!.

While traveling on a major route, the truck just turned off while driving. The truck was stuck in the middle of a two lane major route. Truck would not start or turn on. I was unable to put hazards on or put the truck in neutral. The engine siezed due to the gm recall. After having the engine replaced by a certified gm dealership, a few days later the throttle body stopped working. Again, keeping me stuck. Certified gm dealership had to replace the throttle body.

Vehicle passed initial inspection and had higher viscosity oil installed. After driving for the past six months I noticed a burning oil smell inside the truck. The smell gets intense at times especially during highway driving. The ow-40 viscosity oil is causing high fumes within the cockpit. Please consider checking this issue out during your added investigation into the l-87 engine failure. I shouldn't have to drive with the windows down but I do. I will have the truck inspected during my next oil change next week.

I have a 2023 GMC delnali 1500 and the engine blew up 1-14-26 after the local cmc dealer 2 months ago done a check up recall from GMC that said they would do a test on the engine and cahnge the oil with a heavier weight oil that would solve the problem. After the dealer done the test and changed the oil to a heavier weight I was told all was good. Well 2 months later the engine blew up while I was driving down the road at 50 miles and the truck lost all propulsion. I had the truck towed to my house because noone knew what was wrong with it. I called the local dealer the next day and I had the truck towed to them. They checked the engine and said it blew apart and that GMC will replace the engine and also install a new radiator when all the parts are available. The dealership laura Buick GMC and employees has been fantastic and have supplied me with a vehicle to drive till the repair is finished.

I have the 6. 2l in the truck… I had the recall done due to lower motor crank bearing failure last fall… it passed the recall. They changed the oil cap and changed to a heavier weight oil… this week, the lower engine disintegrated and had to get towed into the dealership dealer is telling me I need a new motor.