general problems of the 2021 GMC Sierra 1500 - part 1

2021 6. 2l GMC sierra denali. Has the l87 engine that is recalled but yet my truck doesn’t fall under the recall although the recall is for 2021-2024 engines. Everything that the engine recall states is the issue with my truck, I have service report from dealership stating that there is wear/breakage of cam shaft/crank shaft amongst other things including cylinder 3 and 5 misfiring , bearings broken , filings in the oil , banging in the engine and safety lights on. My local GMC dealership recommended that the only acceptable action was to replace the engine at my cost of course. This is unacceptable of a supposed reputable large corporation not caring about the “little guy”. The truck only has 136000 kms on it and I was only going 60 km/hr when this happened. Please help as I feel gm knows this engine is faulty but somehow has managed to escape a recall on my VIN number.

P1010 and p2b86 engine code, constant cooling fan on engine. Confirmed by dealership, quoted for coolant control valve. VIN not included in special coverage n252508341 for this known issue. Limited engine power alert, unable to maintain speed on highway. Dangerous condition traveling under speed limit.

At 115,000 the coolant control valve has gone out. Gm acknowledges this issues in 2020 model trucks. My truck is a 21 and displaying the same characteristics. A simple google search will show this is a known issue in 2021 vehicles as well. In 2020 model trucks gm has provided a special 150,000 mile warranty to replace this part. Gm needs to step up and provide a proper warranty/recall for the affected 2021 models.

I'm not sure if they've pulled it out yet. They said two weeks to get motor. Engine started shaking and then started knocking. Had wrecker take it to GMC dealer they said it needs an engine. It is a 2021 6. 2 carbon pro 1500 sierra at4 it did not come up on recall list and I don't know why? it obviously the same problem.

I was driving and my check engine light came on a mile from my house. I drove home and the next morning, I started my truck. It was loud and pulsating like it wanted to stall out. I had it towed to a repair shop. They plugged into the truck and said it was giving code p0016. I had it towed to another place and that it is where it is sitting now. I also received a email from onstar saying "a critical issue with the engine and transmission system in your 2021 GMC sierra crew cab has been detected. P0016 was detected. I searched my VIN # and it says that there are no recalls on my truck. I do see that there was a silent recall on the engine that is in my truck.

The contact owns a 2021 GMC Sierra 1500. The contact stated that while driving at an undisclosed speed, the "add oil to engine" message was displayed. The vehicle was driven to an autozone within two minutes and turned off. Upon inspection of the engine oil level, the contact observed that the dipstick was completely dry. The dealer was notified of the issue, and an appointment was scheduled for an oil consumption test. The vehicle was not yet diagnosed or repaired. The contact stated that the vehicle had been serviced for a routine oil change on April 21, 2026, at 53,590 miles. The contact related the failure to NHTSA action number: rq26001(engine). The manufacturer was not made aware of the failure. The failure mileage was approximately 56,802.

I own a 2021 GMC sierra at4 3. 0l duramax (VIN [xxx]). The vehicle has codes p1098 (coolant control valve performance) and p129f which coincides with the first code. My dealer believes this is consistent with an engine coolant control valve failure. I understand special coverage xxx exists for this issue, but I've been told my VIN is not included. My truck has the exact engine, symptoms, and diagnostic codes addressed by special coverage n252508341, but my VIN is excluded. 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. The contact stated that while turning the ignition on, the "service parking brake" message was displayed, and the check engine warning light illuminated. Additionally, the engine ran rough. The vehicle was taken to the dealer, where it was diagnosed that the engine lifters needed to be replaced; however, the dealer could not diagnose if there was further engine damage until the lifter repair was completed. The manufacturer was made aware of the failure. The failure mileage was approximately 72,530.

Since purchase of my 1500 sierra 6. 2l on 10feb2021, the vehicle has always appeared to burn an excessive amount of oil which is consistent with gm’s 6. 2l engines and has created safety issues leading to sweeping recalls on this engine model from 2021-2024. I have been informed that the engine was consistently down 2+ qts of oil at every recommended oil change (approximately every 5000mi) although gm literature indicated that this level of consumption was usual in their 6. 2l engine. In a jan26 oil change at approximately 35,000mi I was told that my engine was down over 3qts of oil. On 17feb2026 I took my vehicle into my chevy/GMC dealership to request an oil consumption test at ~35, 089mi. On 30jun2026 I returned to the dealership for my 2000mi check-in, at ~37,800mi, and was informed that my vehicle had failed the consumption test. With over 600,000 vehicles recalled since 2024 in the 6. 2l category, my vehicle/VIN has never been associated with a recall. Despite having minimal miles on this engine, I am now financially penalized for repairs because I had just exceeded the initial powertrain warranty and my extended warranty would not cover a pre-existing condition. Gm’s 6. 2l engines have pre-existing issues from the factory and represents a danger to consumers and the driving public because of these failures.

The vehicle has about 38000. The warrantee expired about 6 months ago. About three weeks ago I started the engine, it sounded like a cement mixer filled with rocks. I had it taken to my dealer. They investigated the problem and determined that it has bad lifters and bent push rods. The dealer told me that it is a known problem but it is not covered by the current 6. 2l engine recall.

On June 25, 2026, at approximately 84,000 miles, while traveling approximately 60-65 mph on highway 121 in a posted 65 mph zone, driving my 2021 GMC Sierra 1500 at4 equipped with the 6. 2l l87 engine, multiple warning messages suddenly appeared, including “check esc,” “check parking brake,” “check brakes,” and “check engine. ” the engine began operating abnormally. I drove directly to sewell GMC because I was concerned that the engine could fail or the vehicle could lose propulsion while in traffic. There was no crash, fire, or injury. Sewell GMC inspected the vehicle and confirmed catastrophic internal engine damage. The technician found metal debris in the engine oil and oil pan, damaged internal bearings, and camshaft/lifter damage. Sewell advised that the complete engine must be replaced. The vehicle remains at the dealership, has not yet been repaired, and the engine and failed components should be available for inspection. Before this incident, I had not experienced warning lights or symptoms indicating that an imminent catastrophic engine failure would occur. Gm and the dealership advised that my VIN is not included in the current l87 engine recall because the engine was built in 2020. However, the diagnosed bearing damage, metal contamination, and catastrophic engine failure appear similar to the engine failures addressed by that recall. I am reporting this because an unexpected internal engine failure while driving creates a serious risk of loss of propulsion and a collision.

While driving, the vehicle experienced a sudden and momentary loss of power, similar to briefly applying the brakes, after which power resumed. This was followed by a progressively louder squealing noise. I pulled over to investigate, at which point the engine shut off and a low oil pressure warning appeared on the dashboard. The vehicle would not restart. The vehicle was then towed to a dealership, where initial inspection suggested the issue may be related to the l87 recall involving the crankshaft bearing.

My vehicle began exhibiting symptoms consistent with a failed engine coolant flow control valve. The check engine light illuminated, and diagnostic testing indicated a fault related to the coolant control valve system. In addition, I experienced abnormal cooling system operation, including the engine cooling fans continuing to run after the vehicle was shut off. Vehicle was tested few times in auto zone these symptoms affected the normal operation of the vehicle and are consistent with the condition described in special coverage n252508341. Based on the diagnostic findings and vehicle symptoms, I believe my vehicle qualifies for coverage under this program. I respectfully request that my vehicle be inspected and evaluated under special coverage n252508341 and that any eligible repairs be performed according to the terms of the coverage program.

The contact owns a 2021 GMC sierra. The contact stated that while driving at approximately 40-45, the engine warning light illuminated. There was an abnormal sound coming from the fan. The vehicle was taken to the local dealer, where it was diagnosed and determined that the coolant flow valve needed to be replaced. The vehicle was not included in a special coverage program. The vehicle was not repaired. The manufacturer was not contacted. The failure mileage was approximately 50,000.

While driving my vehicle, the engine and transmission lost power and the check engine light came on. The vehicle went into limp mode and engine propulsion was limited. Had I been traveling at a faster speed, this would have been very unsafe. After coming to a stop, placing the transmission in reverse did not move the vehicle and there was a grinding noise. I was able to savely move forward in limp mode, but the shifting was harsh. I was able to find an empty parking lot to safely park. The truck was towed to jim winter dealership in jackson mi for inspection.

The contact owns a 2021 GMC Sierra 1500. The contact stated that while driving 35 mph, the engine was making an abnormal sound, and the vehicle failed to accelerate. The engine was popping and making cranking sounds, with several unknown warning lights illuminated. The vehicle was driven back to the residence with the issues. The contact referenced NHTSA campaign number: 25v274000 (engine and engine cooling); as a possible cause for the failure; however, the VIN was not included in the recall. The vehicle was taken to a dealer where it was determined that there was metal fragments found in the oil filter, and recommended that the engine be replaced. The vehicle was not repaired. The manufacturer was notified of the failure. The failure mileage was 50,000.

The contact owns a 2021 GMC Sierra 1500. The contact stated that while driving at an undisclosed speed, the reduced power mode and check engine warning lights illuminated. The vehicle was taken to the dealer, where it was diagnosed with coolant control valve failure. The contact was informed that the coolant control valve needed to be replaced. The vehicle was not repaired. The contact was informed that the failure was like the failure description in special coverage bulletin: n252508341. The manufacturer was made aware of the failure but provided no assistance. The contact was informed that the VIN was not associated with the special coverage. The failure mileage was approximately 58,500.

While coasting down or under very light acceleration between 12-20 mph the vehicle has a shudder like driving over a highway rumble strip. While cruising on the highway at 65+ mph, the vehicle has a light shudder or vibration. Vehicle has been checked numerous times for wheel and tire inconsistencies. Brake pads and rotors have also been replaced with no change in issue. Headlights daytime running light changes color from bright white to purple during warm weather. The vehicle has been to 3 different gm dealerships and they acknowledge the issues but do not provide a resolve.

Engine temp rises way above mid-level and will stay there for several minutes before cooling back down to normal temps. 2 different mechanic shops have told me it's the coolant control valve, but want $2500 to fix it. This service bulletin is for the same year, make, model, and motor as my truck, but the dealership said it wasn't covered.

My truck went into reduced power mode while driving on the highway (very dangerous and life threatening) for a coolant control valve failure code (p1098), which has been confirmed by a gm dealership. Gm already has extended the warranty for special coverage n252508341 for selective VIN numbers only and my VIN number is being excluded which isnt safe at all or fair. My truck is a 2021 sierra denali 3. 0l lm2 duramax and has the same exact problem (coolant control valve failure code), and the same exact faulty part, and the same exact motor (lm2) which directly matches the perimeters for the n252508341 special coverage program but my truck isnt being recalled or covered for repair due to them selectively choosing certain VIN numbers to recall only.

2021 GMC sierra after purchase at 4,700 miles had issue with the lifter rods and were replaced at that time. Now the truck has a little over 67,000 miles and once again have the same issue. This appears to be a known issue with this truck and the 5. 3l engines. The truck is in repair and since it is slightly over its warranty of 60,000 miles. The dealer will not cover the repair. Seeing that this is an ongoing and known issues with service bulletins it seems that this should be a potential recall. We were lucky that we identified the issue early and were able to get to the dealer to fix. Otherwise we could have broken down in the middle of our daily commute in the expressway.

I am submitting supplemental evidence regarding my 2021 GMC sierra (VIN [xxx]) for recall query rq26001, campaign 25v-274. Despite multiple repair attempts, my vehicle remains unsafe and non-compliant with gm service bulletin n252494002. The recall remedy was performed deficiently. [xxx] northeast Buick GMC installed a remanufactured short block instead of the required complete engine, reused the original seized-engine oil pan (which continues to leak), and failed to address critical electrical damage. Documentation proves they deleted labor operation 14buz (engine electrical) after their technician noted a blown mega fuse. A second dealer, penske Chevrolet, subsequently deleted labor operation 77cvz01 from my repair order, demonstrating a systemic pattern of ignoring recall-required repairs. Electrical damage has cascaded, resulting in a burnt fuse block and active faults p0615, p0617, p26e4, p26e6, u0623, and u0284. More critically, within 24 miles of my last service, the vehicle developed a new, severe safety failure: the "service brake pad monitor" system failed, accompanied by a red "service system" dashboard alert and a noticeably spongy brake pedal. These brakes were recently serviced, yet this failure introduces a new risk of crash not present prior to the recall "remedy. " gm executive resolution case xxx has provided no resolution, reimbursement, or safety assurance, ignoring all deadlines since xxx. I possess extensive documentation, including service orders showing deleted labor operations and diagnostic logs. I request this update be integrated into the investigation of rq26001, as the current remedy is demonstrably ineffective and has exacerbated safety hazards. The manufacturer’s refusal to remediate these issues, despite my compliance, leaves me with an unsafe vehicle and significant financial loss. I am prepared to provide all supporting records to substantiate this complaint. Information redacted pursuant to the freedom of information act (foia), 5 u. S. C. 552(b)(6).

The truck randomly will not detect that it was shifted into park. Shifting between gears and back to park does not automatically fix the the issue and has taken up to 10 mins to turn the truck off. The adaptive cruise controls stopped working and can still use regular cruise control. Just not adaptive. It appears greyed out. The truck has thrown the error code: p1098, engine coolant control valve position sensor minimum stop performance. The truck would go into limp mode until the error was cleared. This error has appeared 4 times over the past five months. The most recent date of it happening was today. 06/30/2026.

Catastrophic engine failure the connecting rod went through the block. It is my understanding that defective components: manufacturing defects in the connecting rods and crankshafts can reduce oil film strength, leading to severe wear, metal debris, and catastrophic engine could be the proiblem.

Coolant control valve.

Engine coolant control valve position sensor minimum stop performance, and chevy recalled this on this same motor and GMC needs to pays for this as it’s a major problem!.

Coolant control valve not working correctly exhaust fan on high all the time but is never overheating this has been going on for a week it shows there is a 150000 mile warranty on it but not for mine.

I have the same model and year for GMC as bulletin 25na-185, engine coolant control valve failures on 3. 0l duramax (Dec 4, 2025), and am experiencing the same exact issue. Apparently my VIN is not included and I can't get an answer from GMC or the local dealer why it's not covered or how to have it reviewed to be added.

Engine coolant control valve needed to be replaced. Special coverage (n252508341) was issued out by gm to fix this problem on 2021 GMC Sierra 1500 vehicles.

2021 GMC sierra at4, VIN [xxx] , NHTSA campaign 25v-274, gm case xxx. Brake pad monitor failed at 128,923 miles -- 24 miles after leaving penske Chevrolet (released at 128,899, ro xxx, 04/17/2026). Brakes became spongy immediately following service. Monitor disabled entirely to stop recurring red service system alert. Root cause is a burnt fuse block ground fault confirmed in writing by two gm-authorized dealers. Ray skillman (ro xxx, 06/05/2025) documented the fault then deleted labor operation 14buz engine electrical from the recall repair work order. Penske documented verbatim: "all of these other faults share this same ground circuit. " the recall repair at ray skillman used a remanufactured short block instead of a complete engine per n252494002. The original seized-engine oil pan has never been replaced across three dealerships and 128,000 miles. Gm's own part 573 filing states this defect "increases the risk of a crash. " I drove 300 miles on an interstate on 04/22/2026 with active brake warning and no loaner because gm executive resolution refused to authorize one. Three gm dealers have inspected this vehicle. Gm executive resolution team [xxx] ) has not returned calls or emails and has not confirmed in writing this vehicle is safe to operate. Onstar issued a critical alert for p0617 on 04/15/2026. Zero brake faults existed in the 13 months prior to the penske visit. This is a direct continuation of unresolved electrical damage from a botched federal safety recall repair at 384 days and counting. Information redacted pursuant to the freedom of information act (foia), 5 u. S. C. 552(b)(6).

Coolant control valve failing. Warranty not covering this part. Seems to be a manufactured issue. Happening on a lot of 2021 gmnc sierras with the 3. 0l duramax.

My l87 engine has failed due to a manufacturing issue. The recall number for this issue is n252494000. Upon contacting GMC, they state that my VIN number is not included in this recall despite having the same exact issues. I took the vehicle into a mechanic as soon as a problem had arose.

While driving into work, I noticed a knocking sound from the outside of the vehicle. Once parked, upon further inspection I narrowed down the area of the noise to the bottom rear of the engine/front of transmission. Fortunately, I was able to park in front of my office building and wasn’t stranded on the side of the road but under different circumstances it could've been the side of a busy highway or hours from home. I had the vehicle towed to the dealership I originally purchased from, the dealership was able to duplicate the issue with me present. Later that afternoon I was informed that the engine had failed and a replacement would be ordered. There was no prior indication of a problem or warning/cel’s. The engine failed after the dealership had completed the engine recall ( pico test and 0-40w oil change ) related to the vehicle. I am reporting this in hopes that it helps with the investigation. This has been very disappointing for me as I have supported the brand of vehicle for many years. Only to have many issues under 80,000 miles and to lose confidence in the vehicle I purchased and the company.

Driving normal traffic . Started hearing ticking . Check engine light flashing ,service esc and braking system light up. Parking not loud ticking from engine bay.

The afm caused piston flapping and other major engine problems such as abnormal wear. The problem with the engine could have caused a catastrophic failure along the side of a highway. The problem has been diagnosed and the engine has been replaced at my expense. The repairs were made at a local mechanic shop. The engine would start make a loud ticking noise at 2000 rpm or above. The mechanic shop referred to this as piston flapping. This was caused by inadequate oil pressure at all cylinders due to the active fuel management.