general problems of the 2021 GMC Sierra 1500 - part 2

The contact owns a 2021 GMC Sierra 1500. The contact received notification of NHTSA campaign number: 25v27400 (engine and engine cooling). The vehicle was taken to the dealer, where the contact was informed that the vehicle failed an inspection. The contact was informed that the engine needed to be replaced. The vehicle was not repaired. In addition, the contact was advised that parts were not yet available. The contact was advised that it was unsafe to release the vehicle to the contact with the recall unrepaired. The contact was advised that the repair would take two weeks for completion. The contact stated that the vehicle had been at the dealer for more than two months. The manufacturer was made aware of the issue but provided no assistance. The contact stated that he needed the vehicle to use. The contact was advised that the vehicle was number 1,000 on the list for the repair. The failure mileage was 71,000.

Wn a 2021 GMC Sierra 1500 6. 2l (VIN: [xxx] ), which is now experiencing a severe misfire, engine ticking, and diagnostic code p318a. I’ve confirmed this issue is related to gm recall n252494001 for engine connecting rod/crankshaft failure. However, I’ve been told my VIN has not yet been activated for recall repairs, and both the local dealership and GMC support have refused to escalate my case or offer assistance. This is a known safety issue, and I’m now at risk of total engine failure and significant financial loss while waiting for gm to act. Information redacted pursuant to the freedom of information act (foia), 5 u. S. C. 552(b)(6).

When I started my truck in the morning I noticed the check engine light came on and my engine fan started running really loudly. I shut my truck off and let it sit for 5 minutes and restarted it in hopes the check engine light would not appear. Unfortunately it did come back on and the engine fan began running really loudly again. I drove the truck to the nearest mechanic and you could feel the truck was trying to counter the problem by forcing me to drive it in a lower speed. After taking it to a shop to get it scanned to see what the code was. The mechanic said it was reading code p1006 three times. He said this coolant system and is why my engine fan was triggered to run really loudly. But the engine was not over heating as all other indicators showed that temps were normal. The mechanic believes it could possibly just be a faulty wire. However after talking to gm he said if it is this coolant part that needs to be replaced, it could take up to months to fix as the part is on national backorder. Doing more research, it appears others have had this same problem and gm even knew shortly after this model was released that this would happen.

The contact owns a 2021 GMC Sierra 1500. The contact stated that there was an abnormal change with the rpm. There were no warning lights illuminated. 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 dealer received an email from the manufacturer, but the verbiage was incorrect to move forward with the repair. 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 failure mileage was approximately 39,000. VIN tool confirms parts not available.

Complete engine failure on July 17, 2025, related to current recall for defective engine parts on 6. 2l v8 l87 engine. Towed to dealer same day. Dealer continues to report no eta available on replacement engine. Dealer has had possession of my unrepaired truck for 46 days now and counting.

See attached document for complaint.

This vehicle experienced catastrophic engine failure while I was on vacation 400 miles from home. I have researched this failure and there is a class action lawsuit against GMC. My truck has been at the dealer for 25 days and still waiting for authorization from fidelity warranty services. Considering it’s such a common problem I feel GMC should be paying for this. At the very least the warranty company is aware of this problem and purposely delaying the authorization to repair. I just bought a new camper which I cannot use. I am fisherman and cannot use my boat. My beach pass is also on the vehicle. So essentially my summer has been ruined by a company that produced a faulty vehicle and didn’t discord this information to me.

My 2021 GMC Sierra 1500 with l87 engine, covered by recall 25v274. None of my local dealers are inspecting for this recall. This truck is my daily driver and I routinely drive on interstates for my work. Gm has been slow to address this major manufacturing defect and has not remedied the problem. My truck is no longer worth what is was previously and is lowering trade in or sale value. I am requesting that gm buy back my vehicle due to ongoing safety risks and loss of value.

The check engine light came on at one point. I took it to figure out why the check engine light was coming on and the scanner indicated that the nox catalyst was below threshold. I researched it and it is a common issue. The check engine light eventually turned off after a couple of days. About 2 weeks later it came back on. I noticed as I was driving the coolant fans were running at 100% meaning that they were blowing long and hard. So I scanned it and it said that the engine coolant valve was at fault. This is also a common issue with the vehicle, particularly in the 2021 GMC Sierra 1500 3. 0 turbo diesel. It is a faulty part and it costs thousands of dollars to replace. How can these two issues not be on a national recall by gm? they are too common and very expensive to repair. This issue is so common that now the valve is on a national back order. Meaning the parts may not be available for 30-120 days. The vehicle is not safe to drive with a bad engine coolant valve. I have now a rental car for the past 7 days while my truck sits waiting for a valve to arrive and pay thousands in repair just to drive it again.

What component or system failed or malfunctioned, and is it available for inspection upon request? the valvetrain system failed due to broken rocker arms, which resulted in additional internal engine damage. This failure occurred under normal driving conditions. The affected components have not yet been discarded and are available for inspection upon request. How was your safety or the safety of others put at risk? the failure caused sudden engine misfiring and knocking, reducing engine power while I was operating the vehicle. This significantly compromised acceleration and response time, especially during merging and lane changes, which could have led to an accident. Any unexpected loss of power or engine instability at highway speeds poses a serious risk to myself, passengers, and other motorists. Has the problem been reproduced or confirmed by a dealer or independent service center? yes. The issue has been diagnosed and confirmed by an independent certified mechanic, who verified the broken rocker arms and resulting engine damage during inspection. Has the vehicle or component been inspected by the manufacturer, police, insurance representatives, or others? the vehicle has not yet been inspected by the manufacturer, police, or insurance representatives. Only a certified independent mechanic has inspected the failure thus far. Were there any warning lamps, messages, or other symptoms of the problem prior to the failure, and when did they first appear? yes. The check engine light appeared and the engine began running rough and producing a knocking sound. These symptoms occurred just prior to the confirmed failure and prompted me to stop driving the vehicle immediately and have it inspected. Given the seriousness of this issue and reports from other GMC 5. 3l engine owners experiencing similar rocker arm failures, I urge the NHTSA to investigate this potential defect. It poses a real and significant safety risk.

P1098 code - coolant control valve on/off/on/off.

The contact owns a 2021 GMC Sierra 1500. The contact stated while driving approximately 40 mph, the check engine warning light started flashing and the vehicle was shaking with a misfire coming from the engine. Additionally, there was black and greyish smoke coming from the tailpipe. The roadside assistance request message was displayed on the instrument cluster. The vehicle was taken to a dealer where it was diagnosed with a misfire. The vehicle was not repaired. The vehicle was taken to the residence, but the failure persisted. The vehicle was taken to an independent mechanic to be diagnosed, and it was determined that the lifter had dropped, and the engine needed to be replaced. The vehicle was not repaired. The manufacturer was not notified of the failure. The failure mileage was unknown.

The contact owns a 2021 GMC Sierra 1500. The contact received notification of NHTSA campaign number: 25v274000 (engine and engine cooling). The contact stated that while driving at approximately 50 mph, there was a loud squeaking sound coming from the front driver’s side of the vehicle before the vehicle lost power. Simultaneously, the check engine warning light started blinking. The vehicle was pulled over to the side of the road and the sound became louder, before becoming a knocking sound. The vehicle was restarted, and the failure persisted. The vehicle was towed to the residence. The vehicle was not diagnosed or repaired, but a dealer stated that there was as recall associated with the VIN; however, parts were not yet available to repair the vehicle. The manufacturer was not notified of the failure. The failure mileage was approximately 128,000. VIN tool confirms parts not available.

Coolant control valve is faulty. Part number 24001355 for my GMC diesel Sierra 1500. The check engine light goes on and sometimes the engine power will be cut in half to protect the engine. It can be inspected when needed. My truck cannot go as fast and the engine fans sound very loud to cool down the engine. I was 3 hours away from my house when this happened the first time and I wasn’t sure I would make it home. I had to let the engine cool down for about 6 hours after I pulled off of the highway. This has happened two times so far and happens when the ac is on and sometimes when you use the remote start it won’t start the truck remotely and the check engine light goes on. The problem started in July 2025 with 51,000 miles. The engine control module code is p1098. I have asked my GMC dealership to look at the issue and they have told me that the part is backlogged for at least 2 months and they will not look at my truck until the part is available. I haven’t had any other issues with the engine so far and this was the first time a check engine light has gone on.

The contact owns a 2021 GMC Sierra 1500. The contact stated that upon starting the vehicle, there was an abnormal knocking sound coming from the engine. The abnormal sound ceased once the vehicle had accelerated; however, the abnormal sound returned while the vehicle was idling. The check engine warning light was illuminated. The vehicle was taken to the dealer where it was diagnosed that the ball bearing caused a misfire, and two cam lifters needed to be replaced. The vehicle was repaired. The contact picked up the vehicle and on the way home, the engine failed. The contact took the vehicle back to the dealer. The technician test drove the vehicle with the contact as a passenger, and the check engine warning light illuminated. In addition, there was an abnormal sound coming from the engine. The vehicle failed to accelerate as intended while depressing the accelerator pedal. The contact was informed that the engine failed and needed to be replaced along with the fuel body system. The contact was informed that as per GMC, the oil needed to be changed to an oil with a thicker viscosity. The fuel body was replaced, and the oil was changed. The manufacturer was made aware of the failure and offered the contact an amended warranty. The contact was informed that GMC had elected to participate in the procedures under the song beverly act. The failure mileage was approximately 50,000.

See attached document for complaint. I am writing as the owner of a 2021 GMC Sierra 1500 equipped with the 6. 2-liter engine that has recently been included in a significant recall. I've been advised that the engine may need to be replaced entirely. As you can imagine, this is extremely concerning given the scale of the defect and the vital role this truck plays I'n my dayto- day responsibilities.

The contact owns a 2021 GMC Sierra 1500. The contact stated that upon starting the vehicle, the vehicle was idling abnormally, prompting the contact to turn off the vehicle. The contact stated that the check engine warning light was illuminated. The vehicle was taken to the dealer, who diagnosed a failure with the lifter in cylinder #4. The contact stated that the lifter had collapsed into the engine, causing damages to the engine and camshaft. The vehicle was repaired. The manufacturer was not notified of the failure. The failure mileage was 98,000.

The coolant control valve on my truck is causing issues. From doing research, this is an ongoing issue with the 3. 0 duramax. The part is on nationwide backorder and I cannot drive my vehicle in reduced engine power because the only way I can get to work is by taking the interstate. It is madness that gm has not issued a recall or done anything to rectify this issue. Many GMC owners are paying on vehicles that they are unable to drive which is assanine. This part needs to be readily available due to the numerous complaints that have already been submitted in regards to this part.

Have owned my 2021 GMC Sierra 1500 with the 3. 0 duramax for a year and the check engine light has come on multiple times for a "coolant control valve" issue. The truck runs the fans at 100% and puts the truck into reduced power at least once a day. I have read that gm sometimes will not cover this repair under powertrain warranty even though it's an engine problem. Please fix this issue! to answer the previous questions, the coolant control valve is malfunctioning, and the truck is currently at the dealer being inspected. Yes the dealer has said this issue is common on these trucks (confirmed by national GMC in american fork, utah). Yes the check engine light has appeared multiple times. These issues started appearing in June 2025.

Was informed from by gm that my vehicle is involved with a recall an still hasn't been repaired.

Replacement part needed is coolant control valve according to diagnostics at local gm dealer service department after noting check engine light was on. Yes, it is available for inspection. Told unsafe to drive as it would very likely overheat or worse. It has been in the shop for a month (as of June 11, 2025) awaiting a backordered part, which we’re told is a national backorder. No loaner vehicle available and told by service department that they have had another truck in for same problem for several months and that this problem is very common. Please help us with getting the part needed!.

My truck has been consuming oil since new, latest documented consumption test was 1. 25 quarts in 1967 miles. Gm dealership said that is normal and no further diagnosis is required. Gm says acceptable consumption is 1 quart per 2,000 miles. This truck has a 6. 2l engine that is not under the current recall ( n252494000 ). The engine problems affect more vehicles that the current recall and should be investigated.

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 unavailable. The dealer was not contacted and confirmed that parts were not yet available. The manufacturer was not made aware of the failure. The contact had not experienced a failure. VIN tool confirms parts not available.

It started with a emergency brake light coming on, shortly (2 miles) later it started misfiring on cylinder #1 after replacing coil pack plug wire and plug. It then started smoking bad out of the exhaust. I knew gm was having recalls on the 6. 2 engines so I hauled it to the dealer. They told me it was a bad engine and since it had aprox. 62,000 miles on it and no recall it wasn't covered. Since then the dealer called the factory service rep. And he agreed to replace the engine at a 50% reduction in the price, but had no idea when they could get me a replacement engine. After a few days of research on my part I called the dealer again to get a price on how much it was going to cost me? the owner of the dealership ask me to give him a few more days to ask the rep. If he would agree to 100%. My problem now is I don't have it to drive, I can't sell it. And no idea how long it will be before it can be repaired. Plus I am still making payments on it. It is available for inspection at the dealer. If I had of continued to drive, it could have locked up causing a catastrophic accident. In my research it looks like these problems started in 2019 not late 2020 when mine was built. Nc has lemon law complaints going back to 2019 that have been paid out. I currently own a #1 2007 GMC yukon denali 6. 2 with aprox. 389,000 miles and only replaced the transmission recently. #2 a 2008 GMC sierra denali 6. 2 with 279,052 miles, new transmission. #3 a 2011 GMC yukon denali 6. 2 with 234,361 miles and #4 a 2017 Cadillac escalade 6. 2 with aprox. 102,000 miles. All of these are working and driving on a daily bases. I have a lot of faith in these 6. 2 engines until now, I will no longer be buying any more of these engines even though 1 out of 5 aint bad. Thank you for your consideration and for what you do. [xxx] information redacted pursuant to the freedom of information act (foia), 5 u. S. C. 552(b)(6).

Safety recall, unsafe.

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 contact then received a notice that parts for the recall were available. The vehicle was taken to the dealer, and the contact was informed that the recall remedy was for the dealer to use a higher viscosity oil. The contact expressed concerns that the remedy was not a sufficient repair and that the engine was still vulnerable to failure. The vehicle was repaired under the recall. The manufacturer was not made aware of the failure. The contact had not experienced a failure.

While traveling on the interstate the vehicle lost all propulsion and started to rapidly decelerate. Shortly after propulsion was lost the engine turned off completely affecting the steering and braking of the vehicle. The vehicle was towed to the GMC dealership that we purchased it from. Repairs have not begun so I assume it would be available for inspection. We were traveling on a three lane interstate up a grade at 80 mph. Had I not been able to safely get the vehicle stopped and out of traffic or had we lost control going down a grade we would not have been able to stop the vehicle and there would've potentially been a catastrophic accident most likely resulting in injury or death. No the dealership has not diagnosed the failure physically. The service writer did suggest that it sounds like the failure reported from the recall not being addressed. I did contact the dealer about the recall on Saturday may6th. At which time I was informed there was not a solution for the vehicle for my vehicle at that time. There were no warning prior to the incident. After the engine stopped operating there was a warning produced on the instrument panel that read "engine oil hot" and the instrument panel no longer registered any oil pressure.

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 not made aware of the issue. The contact had not experienced a failure.  VIN tool confirms parts not available.

Engine seized while at idle speed and has to be replaced. It was a catastrophic event, but not covered under the current recall for 6. 2l l87 engines.

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 unavailable. The dealer was contacted; however, the contact was informed that parts were not yet available for the recall repair. 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. VIN tool confirms parts not available.

The truck ever since of bought it has been nothing but issues. Starting with the fuel pump issues then electrical issues and most recently the coolant flow control valve. This is my work truck and now I’m out of a truck with no loaner and the dealership has no eta.

The contact owns a 2021 GMC Sierra 1500. The contact stated that while driving at an undisclosed speed, the low oil warning light illuminated. The vehicle was taken to the dealer but was not diagnosed or repaired. The manufacturer was made aware of the failure and referred the contact to the NHTSA hotline for assistance. The failure mileage was approximately 67,600.

My gm 6. 2l v8 engine has seized in less than 100k miles. Thankfully not whilst driving and being potentially harmful to myself or others with the catastrophic failure. This problem is being widely report and continually occurring. Gm is saying that I am not included in the massive recall for this, however NHTSA notes the VIN range as nr and indicates incidents are still occurring. Seems to be a real lemon situation here and even bigger a letdown to uphold consumer safety.

The camshaft cover in pre 2021 3. 0l duramax motors is leaking oil/def internally causing oil loss. This is something gm has noted in their TSB pages but has not issued a recall over. This is a hazard to emissions, oil consumption, and the def system. Also could result in premature engine failure.

My truck has a known recall from GMC which results in total loss of propulsion. It has not failed yet, but this is dangerous to me, my family/kids, and potentially others on the road. I have made multiple attempts to speak with GMC about the issue and also my local dealer. Neither group will provide concrete information as to when they can look at/service my truck even though there is a known remedy - https://static. Nhtsa. Gov/odi/rcl/2025/rclrpt-25v274-1598. Pdf I brought my car into the dealer December of 2024 for brakes and also a rattling noise since it was uncharacteristic. Noises can be indicative of this larger problem (which I know now and didn't then) but they "didn't hear a rattle" and the "condition could not be duplicated" which is patently false since it still makes the noise/has gotten worse. Since then, I have taken the following actions: - I called and spoke with the local dealer service team on 5/5 - was told since it's showing incomplete, no remedy available there was nothing they could do - spoke with GMC on 5/5 - they directed me to the local dealership - made an appointment online on 5/10 to get my truck serviced and to check for this problem - they immediately called me first thing on Monday 5/12 to cancel my appointment and again tell me there is nothing they can do about this issue - I have continued to express my safety concerns to both parties - I spoke to GMC today, 5/30 and was told that there is no timeline for the issue (with my VIN) even though the remedy is known - an appointment is scheduled on 6/12 with my local dealership, but if I recall status hasn't changed, they will not check for this problem.