general problems of the 2021 GMC Sierra 1500 - part 1

The contact owns a 2021 GMC Sierra 1500. The contact stated that while driving at an undisclosed speed, the engine seized. The contact was unaware of a warning light being illuminated. The contact stated that while attempting to start the vehicle, the vehicle failed to start. The vehicle was towed to the dealer, where it was diagnosed with engine failure. The contact was informed that the engine needed to be replaced. The vehicle was not repaired. The contact referenced an unknown engine recall; however, the VIN was not under recall. The manufacturer was made aware of the failure, and a case was filed. The contact was advised to report the failure to the NHTSA hotline. In addition, the contact was informed that the VIN for the vehicle was a canadian VIN, and the mileage was displayed in kilometers. The failure mileage was approximately 120,000.

Had a "trans hot warning" light. Dealership said it was internal valve body failure. They said there is recall on this for other engine types even though this is same issue. I think GMC needs to expand their recall.

The engine is knocking and running rough. I took it to christian brothers automotive in newnan GA and the advised engine replacement.

The contact owns a 2021 GMC Sierra 1500. The contact received the recall letter for NHTSA campaign number: 25v274000 (engine and engine cooling). The contact called the local dealer, who confirmed there was no information from the manufacturer to move forward. The vehicle was not diagnosed or repaired. The manufacturer was not contacted. The contact had not experienced a failure.

The contact's grandson owns a 2021 GMC Sierra 1500. The contact stated that after the vehicle was purchased from a private seller and driven 258 miles, while his grandson was merging off the exit ramp, the engine seized. The low oil pressure warning light was illuminated. The contact stated that the check engine warning light was illuminated prior to the failure. The vehicle was towed to the contact's residence. The contact scanned the vehicle and retrieved dtcs: p0011, p0016, p006dd, and p0521, stored dtcs: p06dd p0011, and permanent dtcs: p0011 and p0016. The engine was replaced by the contact. The local dealer was contacted for parts. No further information was available. The manufacturer was not contacted. The failure mileage was approximately 100,148.

I just surpassed my extended warranty (5 year/100,000 miles) by a couple of thousand miles and my coolant control valve has gone out. The problem is so common that the part is on back order for months at a time. Gm says that they issued special coverage for 2020-2022 models, but my dealer is telling me that my VIN is not covered. They want to charge me $2,400 to replace it. This is insane. It’s a very common problem that they know about and it’s going to almost break me. We need help!.

Took the vehicle to the dealer because of an engine noise. It had issues with the valves knocking when it had around 1000 miles. I took it in and now the truck has around 67,000 miles and I’m being told it needs a new engine because of a bent rod in the engine. I was told that I need a new engine. Previously I had a lot of other issues with the front wheel hubs clicking. But, this truck didn’t even make it to 5 years and now it needs an engine.

My wife was driving at highway speeds with all are kids when the trucks motor suddenly loss all power all check engine lights illuminated and what I'm assuming had major engine failure causing rod knock.

Heard a ticking noise then check engine light started blinking along with service esc and parking brake. Took it to the dealer and I had a bad lifter again. I was previously repair for lifters under warranty a little over 2 years ago.

On 10/21/2025 as I was traveling on the highway in kansas at 60 mph, the vehicle lost power and the engine went into limp mode immediately reducing the speed dramatically. Multiple warning lights flashed on the screen. I was able to get the truck to the side of the highway. The vehicle never started again. I was informed by the dealer that the vehicle would need a new engine.

I own this 21 GMC sierra with a 6. 2l. This VIN is not part of your current recall. But my truck is at a dealership waiting on a replacement engine. I was told that the engine locked up in the bay. Not sure if any lights came on before the engine failed, the dealer did not go into that much of detail. The truck is sitting outside waiting on the engine, not sure if gm made then do any failure analysis or just said its a 6. 2 were sending an engine.

I just took my 2021 GMC sierra 1503. 0 duramax diesel into faulkner Nissan, today 10/18/2025 m, to have that recall fixed. I picked it up from the dealership and drove about 10 miles before it went into limp mode and reduced power mode while I was driving and started to shift very roughly and I’ve never had any issue like this before they supposedly fix this recall, I think the software patch made it worse in my case. Now my vehicle is throwing a bunch of different transmission error codes, that it has never produced , and it is going into reduced power mode,as I’m driving and going into limp mode as I’m driving, which you never has done before and it feels like it’s stuttering in early gears now and the idle was really rough it didn’t idle at a specific spot it went from 800 to 1300 back down to 800 when it should’ve just been idle at 800. I don’t know what to do. It seems like this recall made the problem worse for me and my truck in this case, I don’t know what to do and I don’t know where to go. I hope you guys can help us. Please make GMC take responsibility before somebody gets killed. If they haven’t already this issue is extremely dangerous and I’m sure is destroying the transmission. I don’t feel comfortable driving my family in my vehicle anymore because of this issue it is terrifying….

I was traveling home from work and lost all power to the vehicle while driving. No warning lights, check engine lights came on. I was able to cross traffic and park it in a business place. I had it towed to a chevy dealership for diagnostic. They said that the timing chain came off and I would need a new engine. I had it towed to a auto mechanic shop for a second opinion and they gave the same result. The vehicle is only 4 years old with 92,000 miles on it. When I lost all power to the vehicle, I did not hear any strange noises.

Vehicle showing signs of a failing coolant flow control valve and/orcoolant temperature sensor. - ac takes a long time to cool down - engine fan will stay on after the vehicle is shut off - I often see the notice of “a/c off due to high engine temp” from what I can find, this issue I’m experiencing is a known point of failure in this vehicle make/model/year. On 10/10/2025, I took the vehicle to fountain Buick GMC service in orlando, FL. The service manager recognized the symptoms immediately, and even knew right away that the part to fix it was on back order - further bolstering that it is an issue that gm is aware of and deals with regularly. Per the service manager, gm’s initial response was to issue a “pay to play” software update that is covered under the 3yr/36,000 warranty, but not the 5yr/100k. Out of warranty, this “solution” costs $499. 99, and has a < 10% degree of success. If the update doesn’t fix the issue, then it would be covered. However, the need for the software update was not communicated to consumers. Regardless, since the issue is not yet severe enough to be recognized via code (despite symptoms, pictures, and video), gm will not take any action under warranty towards fixing it at this time. The vehicle’s 5yr/100k warranty expires on 10/15/2025. If the code throws on 10/16/2025, it will not be covered under warranty, but * be covered under dealer assistance. And regardless, the $499. 99 charge will apply, independent of warranty coverage. More important than the money is the safety. The engine’s temperature is not being regulated, the symptoms I’m experiencing are terminal, and this issue will not be fixed on its own.

Dtc code p1098 present related to faulty coolant control valve on 3. 0 duramax diesel engiine. This is a known issue with this engine and is supposed to be covered under the 100k mile powertrain warranty. Previously took vehicle into dealership for repair involving replacement of the coolant control valve but was told reprogramming of the ecm was required first step per gm repair bulletin. Reprogramming cost me $195 and was told this was not covered under the 100k powertrain warranty. Now, a few months later, the same issue and dtc code p1098 happened again while driving on freeway at freeway speeds and caused vehicle computer to limit speed of the vehicle which caused hazardous situation in construction zone as was not able to maintain speed of traffic while towing trailer with boat. I also understand that gm has issued special extended warranty related to this coolant control valve in September 2025 which extends the warranty coverage up to 15 years and/or up to 150k miles but I was told at the dealership that my VIN# does not qualify for this extended coverage for some unknown reason?.

While traveling to work at 75mph, a sudden an unexpected malfunction of internal engine components caused a loss of propulsion.

The contact owns a 2021 GMC Sierra 1500. The contact had received notification of NHTSA campaign number: 25v274000 (engine and engine cooling). The vehicle was taken to the dealer where an inspection was performed on the engine. The contact was informed that the vehicle had passed the inspection, and the mechanic added a higher viscosity oil, installed an oil fill cap, replaced the oil filter, and updated the owner's manual. The contact stated that the remedy failed to address or repair the possible defect with the engine. The contact stated that the remedy resulted in a higher cost for oil changes, and fuel economy had decreased from 21 miles per gallon to 18 miles per gallon. The manufacturer was made aware of the issue and the contact was provided a case number. The contact stated that the vehicle had not been repaired. The failure mileage was unknown.

On [xxx], at approximately 15,873 miles and while on the freeway approximately 30 miles from my home, my GMC Sierra 1500 with the l84 engine experienced a failure of the dfm lifter assembly. This required a significant engine disassembly and the replacement of multiple valvetrain components. This repair was performed at gold rush Chevrolet in auburn, CA, as documented in the enclosed service invoice. Gm has issued technical service bulletins and product communications addressing similar lifter failures in gen v small-block v8 engines with dfm/afm, including service update n212353840, pip5776, #19-na-219, and related updates. Industry coverage and owner reports and current class action lawsuits indicate that these failures can recur, even after initial repairs, due to the high cycling frequency of the dfm lifters. Given the nature of the defect and gm’s documented acknowledgement of the issue, I am requesting that gm extend the powertrain warranty coverage for the engine and related valvetrain components for a period of 10 years,100,000 miles as a goodwill policy adjustment. A warranty extension would ensure customer confidence and protect against the significant cost of a repeat failure. Information redacted pursuant to the freedom of information act (foia), 5 u. S. C. 552(b)(6).

After having transmission issues which was replaced under warranty, within 300 miles, the engine failed. The vehicle has now been sitting at the dealership since October 7, 2025 waiting for a replacement engine. There is no timeline available for the replacement engine as they are currently backordered. Absolutely ridiculous.

I purchased a 2021 GMC Sierra 1500 denali (VIN: 3gtu9fel5mg467929) from j. C. Lewis Ford in pooler, georgia. The dealership did not disclose an active federal safety recall (NHTSA campaign number: 24v-xxx / gm n252494000) related to engine connecting rod and crankshaft defects that can result in sudden engine failure and loss of propulsion. The blue certified delivery document they had me sign includes a section requiring disclosure of any open recalls, but they left the recall section blank and checked that all recalls were explained to me. No disclosure of any recall occurred during the sale. The vehicle developed engine problems within days and is currently in GMC service. The nondisclosure put me at risk of driving a vehicle with a known safety defect. I am reporting this as a dealer nondisclosure of a federal safety recall.

I am an active u. S. Air force member. My 2021 GMC Sierra 1500 failed gm recall n252494003 on sept 29, 2025 (l87 engine loss of propulsion). Gm states this defect can cause sudden engine failure and loss of propulsion, increasing crash risk. Despite the confirmed failure, ocean Cadillac (miami, FL) told me to keep driving the unsafe vehicle and refused all courtesy transportation. The service manager admitted in writing that the engine failed, the defect can cause loss of propulsion, and the replacement engine is delayed under gm national control for up to 3 months — yet they still denied me a loaner or rental. His statements contradict the gm documents he attached: • gm bulletin dcs7222 says courtesy transportation can be provided during l87 recall downtime and dealers must consider loaners/rentals. • gm faq n252494002 says courtesy transportation is available for this recall. • gm faq lists recall symptoms (check engine light, hesitation, high rpm, reduced power) — not battery drain. • gm states: “if the engine fails, the vehicle will lose propulsion. ” ocean Cadillac ignored these rules and put me back on the road in a known unsafe vehicle. As an american manufacturer, gm has a responsibility to protect american drivers. Their failure to follow recall procedures placed me, my family, and other motorists at risk. I request NHTSA investigate whether gm/ocean Cadillac are complying with recall safety requirements and whether customers are being told to drive unsafe vehicles after confirmed failures.

Constant engine issues, cams, lifters. Transmission problems. These engines in these vehicles need to be recalled. I have bought 6 of these trucks and all of them have the same issues. Spending 14k on new engines one after another is ridiculous. These are classified as “work” trucks and can’t handle “working” .

I was driving at highway speeds probably doing 55 and another vehicle pulled out in front of me forcing me to slow down rapidly. That’s when my wheels locked up and my vehicles wheels locked up in the middle of the highway. Screeching tires, almost like the vehicle went into park for a second. After about two seconds, I was able to continue driving a highway speed no check engine lights no error codes. It felt like I just hit something nearly gave me a heart attack. My family was in the car. It felt like we all almost died. It was terrifying. This transmission issue recall situation has happened to me more times than I can count. Now it’s almost a guarantee that if you have to shift too hard too fast it locks up the differential and it is terrifying. Every time.

Engine lifters bent a pushrod and scratched my camshaft in my engine causing me to be stranded with minor children. 3rd time since I bought this in 2021 that I have had engine faults in this truck.

The contact owns a 2021 GMC Sierra 1500. The contact stated that while driving at an undisclosed speed, the vehicle inadvertently lost motive power. The contact was able to pull over to the shoulder of the roadway, where the vehicle failed to restart. No warning lights were illuminated. The vehicle was not taken to the dealer or an independent mechanic. The vehicle was not repaired. After investigating the failure, the contact related the failure to NHTSA campaign number: 25v274000 (engine and engine cooling); the VIN was included, but parts were not yet available. The manufacturer was not notified of the failure. The failure mileage was 60,000.

The contact owns a 2021 GMC Sierra 1500. The contact received notification of NHTSA campaign number: 25v274000 (engine and engine cooling); however, the part to do the recall repair was not yet available. The local dealer was contacted. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The manufacturer was made aware of the issue. The contact had not experienced a failure.

Coolant control valve failure. Instantly reduces power on truck. National back order on parts. No remedy.

The contact owns a 2021 GMC Sierra 1500. The contact stated that the engine was previously replaced under warranty. The contact stated that the vehicle had been experiencing excessive oil consumption and required three quarts of oil every 30 days. The contact received notification of NHTSA campaign number: 25v274000 (engine and engine cooling); however, the part to do the recall repair was not yet available. The contact stated that while driving 70 mph, the vehicle shuddered abnormally and there was an abnormal metallic sound coming from the engine before the vehicle lost motive power. There was no warning light illuminated. The contact was able to pull over to the side of the road. The vehicle failed to restart and was towed to the residence. The local dealer was contacted and informed the contact that a service advisor would return the call. The vehicle was not diagnosed or repaired. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The manufacturer was not made aware of the failure. The failure mileage was approximately 129,000.

? background: •2021 GMC sierra denali – 6. 2l v8 •VIN included in gm’s engine defect recall (connecting rod/crankshaft) •recall status shows “no current remedy available” •defect acknowledged by gm can cause “engine damage, loss of propulsion, or complete engine failure. ” timeline of events: •~1 month ago – truck began running rough with noticeable ticking/knocking noise. •dealer could not schedule appointment for 3 weeks. •08/08/2025 – dealer inspection confirmed failed lifters and damaged camshaft. •repair estimate: $9,300 (see attached dealer estimate). Connection to recall: •lifter and camshaft are internal engine components dependent on the same lubrication and oiling system as the crankshaft/connecting rods cited in the recall defect. •the defect’s potential to contaminate oil and cause internal engine damage makes this failure consistent with recall-related damage.

This recall has been coming for some time now its out and gm still has no plan or action. This is our only auto and my understanding if this issue happens it could cause loss of life. I am concerned for my wife driving to work every day and what happens if we want to take a trip. We need resolution on this. Apr 24,2025 manufacturer recall numbern252494000 NHTSA recall number25v274 recall statusrecall incomplete, remedy not yet available [xxx] information redacted pursuant to the freedom of information act (foia), 5 u. S. C. 552(b)(6).

The contact owns a 2021 GMC Sierra 1500. While the contact's husband was driving at an undisclosed speed, the contact noticed an abnormally bumpy ride. The contact felt as if the vehicle was driving over rocks. The check engine warning light was illuminated. The vehicle was taken to the dealer where it was diagnosed with engine failure. The contact was informed that the engine needed to be replaced. The vehicle was not repaired. The contact received notification of NHTSA campaign number: 25v274000 (engine and engine cooling); however, parts were not yet available for the recall repair. In addition, the contact stated that the vehicle had been at the dealer for more than two months awaiting parts. The manufacturer was made aware of the failure and a case was filed. The failure mileage was approximately 80,000.

I receivd a recall on my 2021 GMC denali 1500 , 6. 2 engine recall # n252494000. Made an appointment with carroll GMC, at 1455s. Tamiami trail, venice , FL, on 7/29/25 at 11am. I showed up for my appointment and they denied checking my truck on the recall stating they did not have the remedy to fix the problem so therefore they were not going to check my truck for the recall. . . . . . I have a trip coming up and now I a afraid to go on the highway in case my truck loses power and I get in an accident. . . . . . . . . . . . My truck should have been checked for the recall regardless of the remedy to fix it. . So at least I know weather it is safe to drive or not.

I own a 2021 GMC denali with a 6. 2l v8 l87 engine and 45,500 miles. I have confirmed the presence of metal shavings in the oil and oil filter, indicating that the engine is beginning to fail. When I took the vehicle to my local dealership, I was informed that there is currently no fix for this issue and was advised to continue driving the vehicle. This poses a serious safety risk—not just to me and my family but also to others on the road. A sudden loss of power could lead to a dangerous accident, and I do not want to be responsible for something preventable that could harm innocent people. My concern is that gm is aware of this engine issue but has instructed me to keep driving the vehicle, despite the known defect. How can gm be allowed to avoid accountability for such a critical safety matter? if a fatal accident were to occur, would the responsibility fall on gm or the NHTSA for failing to act? it’s also troubling that gm continues to profit by selling new vehicles, including the 2025 models, with similar issues, all while neglecting to provide solutions for affected customers like me. I purchased this $80,000 truck in good faith, but now no dealer wants to trade or buy these trucks without me taking a significant financial loss—something gm should be responsible for. As a taxpayer, I find it unacceptable that we bailed out gm in the mid-2000s, yet they continue to disregard accountability for their actions. I urge the NHTSA to take this issue seriously. A specific deadline should be set for gm to resolve this issue, and they should face daily penalties for every day they fail to provide a fix. If no resolution is possible, full refunds should be mandated. Please address this issue promptly, as it affects real people’s safety and financial well-being every day.

The contact owns a 2021 GMC Sierra 1500. The contact stated that while driving at an undisclosed speed, the vehicle stalled, lost motive power, with smoke coming from the engine compartment. There was no warning light illuminated. The vehicle was towed to the residence. The contact attempted to start the vehicle and noticed a knocking sound coming from the engine with the check engine warning light illuminated. The contact received notification of NHTSA campaign number: 25v274000 (engine and engine cooling). The dealer was contacted and informed the contact that parts were not yet available. The dealer informed the contact that the vehicle had a salvage title and would not be repaired under the recall. The manufacturer was made aware of the failure and a case was opened. The failure mileage was approximately 48,000. VIN tool confirms parts not available.

The coolant control valve (part # 24001355) has failed. Apparently this is the case with many vehicles and gm will not/can not get replacement parts. This should be a recall.