2021 GMC Yukon Owner Complaints

The vehicle (2021 GMC Yukon Denali) has suffered three consecutive, catastrophic failures of the engine's rear main seal. Following the initial replacement—which requires mechanics to unbolt and drop the vehicle's exhaust system—a massive exhaust leak developed in the engine bay. The vehicle is now actively pumping toxic exhaust fumes directly through the air conditioning vents into the passenger cabin, creating an immediate carbon monoxide inhalation hazard. The underlying mechanical issue is a chronic failure: either excessive crankcase pressure (clogged PCV system) is repeatedly blowing the engine seals, or the dealership technicians failed to properly align and seal the exhaust flanges/gaskets upon reassembling the vehicle. General Motors corporate has been notified of this recurring, unresolved safety defect. The vehicle is currently undrivable due to the severe buildup of fumes inside the passenger compartment while the engine is running.

NHTSA ID

11776699

Incident

Oct 13, 2026

On XXX, at [XXX], my vehicle’s engine locked up, causing the vehicle to shut off while I was driving at 65 mph on a two-way highway. The vehicle could not be safely driven. My family and I were stranded on the side of the road, where semi trucks passing at highway speeds forced us to remain in the vehicle. Unreliable cellphone service and OnStar connectivity limited my ability to request assistance, communicate my location, or obtain timely support, making Arizona Department of Public Safety (DPS)-arranged towing necessary. DPS requested the tow at approximately 7:52 p.m.; it was completed at approximately 11:25 p.m. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11776111

Incident

Sep 3, 2026

The contact owns a 2021 GMC Yukon. The contact stated that while her husband was inspecting the vehicle, he discovered that there was no oil in the engine. The vehicle was taken to the dealer where it was confirmed that the engine was consuming an excessive amount of engine oil after performing an oil consumption test. The manufacturer was notified of the failure and agreed to cover 20% of the cost of the repair. The failure mileage was approximately 79,000.

NHTSA ID

11775726

Incident

Feb 10, 2026

Mileage

79,000 mi

My driver side headlamp went out while driving. The amber turn signal light remained on after I shut the engine off. This made my battery die. The headlamp is full of condensation and none of the lights are working. I had to replace the battery and have been told by GM that they've had many complaints but aren't issuing a recall yet. Can you please advise me. Thank you

NHTSA ID

11775680

Incident

Aug 9, 2026

While stopped in a parking lot. I returned my vehicle to drive home, and the car would not start. I had it towed to the dealer. They did a diagnostic inspection for "crank-no-start ". Two trouble codes: P0340 intake single camshaft ignition sensor circuit and P00C6- fuel rail pressure load during engine cranking. Performed diagnostic checks and suspect a broken timing chain and timing tensioner that causes the bottom of the engine to free spin while the top 0.5 does not. These engines are known as interference engines, and anytime there is a mismatch between the top 0.5 and the bottom 0.5, there is the potential for catastrophic failure due to the design of the valve train and bottom 0.5 of the engine. The technician suggested a full engine replacement. I went to the dealer and spoke with the Service Manager, Greg, and he stated that he would reach out to GMC because the VIN number was not part of the recall, although the YEAR/MAKE/MODEL is. I also reached out to GMC to open a claim. To date, I have not heard back, and they have not yet accepted responsibility for replacing the engine.

NHTSA ID

11774191

Incident

Oct 25, 2026

As I was driving down the road at 60mph, no dash lights or warnings were present. All of a sudden, my 2021 yukon lost all power and I nearly crashed as I was in heavy, fast paced traffic. I got to the side of the road, and it was at this time the engine light came on. Car died and wouldnt start back up.

NHTSA ID

11773740

Incident

Oct 23, 2026

About 1 month ago while driving down the highway, my vehicle dash and screen went completely back for a few seconds and came back on. As if it shorted out

NHTSA ID

11773385

Incident

Aug 31, 2026

crank/rod failure on 6.2 engine. yes it is available same as other people with blown 6.2s yes, GMC dealer diagnosed crank failure no no. engine still runs but is knocking and squealing but dies after a few mins and won't restart till it cools off

NHTSA ID

11773344

Incident

Oct 15, 2026

Our 2021 GMC Yukon Denali has repeatedly experienced sudden, violent braking and apparent rear-wheel lockup without the driver applying the brakes. These incidents occur without warning at highway speeds, moderate speeds, and in traffic. The vehicle abruptly decelerates, fishtails, loses stability, and produces smoke. The wheels have locked severely enough to leave skid marks on the roadway. This creates an immediate risk of losing control or being struck by another vehicle. We took the Yukon to Alpine Buick GMC on October 12, 2026. After eight days, the dealership reported that it could not reproduce the malfunction. However, its written findings confirm that an engineering case was opened and GM engineering recommended replacing the transmission valve body based on data collected from other vehicles with related concerns. The dealership proposed approximately $3,300 in repairs without providing diagnostic evidence establishing that the valve body was definitively responsible or that replacement would resolve the dangerous condition. We declined the repair and paid $229 for diagnostics. GM recalls 24V797 and 26V085 address transmission valve failures capable of causing unexpected rear-wheel lockup. Although our gasoline-powered Yukon is excluded from these recall populations, it is exhibiting similar dangerous behavior, and GM engineering has recommended replacement of the same type of component. Exclusion from a recall based on VIN does not establish that a vehicle is free from a similar safety defect. We request that NHTSA investigate whether this failure extends to 2021 gasoline-powered Yukons and other GM vehicles outside existing recall populations. This is a recurring, unpredictable loss-of-control hazard that could result in a serious or fatal collision. It has come very close on E470 in the center lane at 75 mph with cars in all positions around us. Do you want YOUR family in one of the cars around us?

NHTSA ID

11772468

Incident

Aug 21, 2026

VEHICLE: 2021 GMC Yukon, 5.3L V8 (L84). VIN: [XXX]. Mileage at failure: approximately 88,000. Component: Engine. INCIDENT DATE: XXX While I was driving on a highway, the engine began to misfire and I heard a ticking noise. The check engine light then began flashing, indicating a severe misfire. I pulled off the highway immediately to a rest area. The vehicle was towed to a GMC dealer. The dealer's diagnosis suspected failed valve lifters, and the repair orders call for a misfire diagnosis with the Bank 1 cylinder head removed, and replacement of the camshaft, lifters, and related parts. This failure caused sudden loss of engine performance at highway speed. The engine began smoking. My family and I were in the vehicle, and we were fortunate there was a safe place to stop. I believe this is a known defect. GM Service Bulletin PIP5776, "Misfire Due to Collapsed Lifter," covers 2021 GMC Yukons with the 5.3L L84 engine. It describes a misfire with a bent pushrod leading to a collapsed lifter or a lifter that comes apart, and it attributes the cause to an internal lifter concern. Many other owners of GM V8 trucks and SUVs have reported the same failure, and a class action over the AFM/DFM lifters has been pending against GM in federal court in [XXX] since 2021. I bought this vehicle new and have maintained it. This is the second time this vehicle has left my family stranded on a highway. In 2024, a separate known issue left us, including three children under [XXX], on the side of a major highway about 7 hours from home. GM repaired that issue. For the current failure, GM has not agreed to cover the repair. It has offered $5,951.39 toward an engine replacement, which would leave me responsible for $13,886.59 plus teardown labor. I am filing this complaint so NHTSA is aware of this failure, which can cause sudden loss of power on the highway. GM case number: XXX. Dealer: Fred Beans Buick GMC, [XXX]. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11772421

Incident

Oct 7, 2026

Bought 2021 GMC Yukon Denali new. Transmission failed at 70,000 miles. Engine has now failed at 111,000 miles. Both diagnosed at Capital GMC Atlanta, GA. Cost to replace transmission $8k (GMC paid half). Cost to replace engine $12k (GMC offered no assistance). Engine failure not related to current engine recall/investigation on GMC 6.2L V8 engines. This failure was on the top vs on the bottom (current recall).

NHTSA ID

11771584

Incident

Oct 9, 2026

I believe it’s a transmission. While driving down the interstate and the car just won’t get up and go like it should, and I’m gonna get rear ended. I’ve I’ve taken it to the dealership three or four times. I keep telling me nothing’s wrong.

NHTSA ID

11771545

Incident

Sep 1, 2026

In late February / early March 2026, at approximately 139,000 miles, my 2021 GMC Yukon Denali with the 6.2L V8 (L87) engine developed a loud knocking/rattling noise that sounded like a loose part inside the engine. The vehicle kept running, but the noise persisted. I took the vehicle to a GMC dealer. The dealer checked the VIN and told me there was no recall covering my vehicle. The engine was found to have internal damage consistent with connecting rod / bearing failure. A replacement engine was quoted at approximately $8,000. Because I could not afford that, an independent mechanic in Connecticut rebuilt the engine for approximately $5,500 in total (about $4,500 in parts plus $1,000 in labor), paid out of my own pocket. I have all the invoices for the repair. This failure appears to be the same connecting rod and crankshaft bearing defect covered by Recall 25V-274 for other 2021–2024 vehicles with the 6.2L L87 engine, but my VIN is excluded from that recall according to the dealer and the NHTSA/GM VIN lookups. No crash and no injuries occurred. I am reporting this failure so it is documented in NHTSA's investigation of L87 engines outside the recall population, and I respectfully request a review of why this VIN was excluded and whether reimbursement for the repair is possible if coverage is expanded.

NHTSA ID

11770913

Incident

Mar 1, 2026

The contact owns a 2021 GMC Yukon. The contact stated that while driving, the engine started making abnormal sounds. The vehicle was towed to a dealer. The manufacturer was notified of the issue. The dealer confirmed that the vehicle had experienced lifter failure and stated that further diagnostic tests were needed to determine if the engine needed to be replaced or if the lifters only needed to be replaced. The failure mileage was approximately 69,000.

NHTSA ID

11770195

Incident

Oct 5, 2026

Mileage

69,000 mi

I was driving normally, going up a hill and the car skipped and lurched forward. Then when i touched the gas pedal the car would not accelerate but the rpms would increase. When I was able to pull over, the car would not reverse, the engine would rev when i pushed the gas pedal but it would not move. I drove it directly to a mechanic down the road and he believes the transmission is shot and agrees that it is part of the problems that GMC is having with its transmissions, and it seems as though my car should also be included. This was an extremely dangerous and frightening thing to happen to a car with no warning whatsoever. I was lucky not to have been in an accident.

NHTSA ID

11769793

Incident

Oct 7, 2026

While driving on the highway with my child in the car, the car suddenly began shaking and warning lights to check the power train came on the dash. There was also a loss of power in acceleration. Other error codes (303) also appeared with the check engine light also coming in. Upon checking the code later once home, it indicated there was an issue with the lifters. The car was then towed to the dealership where it was confirmed there are issues with both the lifters and the cam shaft and both need to be replaced.

NHTSA ID

11769396

Incident

Sep 18, 2026

I purchased this vehicle new in 2021. In XXX, the vehicle started shaking while driving then suddenly cut off. Mileage was a little over 12K. Diagnosis was an engine lifter issue. The dealership replaced all 16 engine lifters. The vehicle now has a little over 52K miles on it. The engine lifters have failed again. This is a known safety issue for this (and other GM vehicles) manufactured in the same timeframe. However, GM has not issued a recall. I am now looking at having to replace the lifters at my cost and/or driving an unsafe vehicle. I have a wife and [XXX] son. This is an untenable situation. GM must issue a recall and correct this issue. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11768352

Incident

Sep 30, 2026

The contact owns a 2021 GMC Yukon. The contact's wife stated that while driving at an undisclosed speed, the vehicle lost motive power and was unable to restart. The vehicle was towed to a dealer, where it was determined that a fuse had failed and needed to be replaced. The vehicle was repaired. The contact's wife stated that while driving 55 MPH after the repair, the vehicle unexpectedly shifted into neutral, stalled, and lost motive power. The vehicle was unable to restart. The vehicle was towed to another dealer, where it was diagnosed that metal shavings were found in the oil, causing the engine to seize. The contact was informed that the engine needed to be replaced. The contact associated the failure with NHTSA Campaign Number: 25V274000 (Engine and Engine Cooling). The manufacturer was made aware of the failure on the manufacturer's website and by phone, and a case was opened. The approximate failure mileage was 72,850.

NHTSA ID

11767854

Incident

Sep 11, 2026

Mileage

72,850 mi

I drove my car on Saturday and nothing was wrong with it. I opened my car door on Monday morning or work and my driver side seat was twisted. There was no warning signs nothing. The dealership said that a rod is not working probably. I have had two other yukons and drove them for almost 10 years and never had this issue. This is my third one and only has 41,000 miles and has been to dealership to be serviced. This should not have happened. According to research I have done it states that there were some TSBs on mechanical failures in the seats. I was directed to ask for the dealership to contact GM goodwill assistance on my behave since I have been a loyal GM customer. This is a serious safety concern if this would have happened while I was driving.

NHTSA ID

11767675

Incident

Sep 28, 2026

General Motors, Orr GMC and Sewell GMC are purposely concealing issues and service records related to my vehicle. I believe it is intentional fraud on their part to mislead the public, legal/judicial officials and oversote authorities about the severity the L87 engine failures and excessive oil consumption. They have lied about the status of the vehicle during oil consumption tests, refused to document test results and even rescinded their offer to replace the engine when I refused to sign their release of liability that contained false statements. Orr GMC also completed work on my vehicle without my knowledge or consent that led to worse issues. This is a safety issue for the public and for my family and I.

NHTSA ID

11767182

Incident

Aug 6, 2025

My 2021 GMC Yukon has approximately 36,900 miles. On September 12, 2026, the vehicle was at an authorized GMC dealership and passed a state safety inspection. On September 19, 2026, the check-engine warning light illuminated and I returned to the dealership. The dealer performed diagnostic testing and told me the fuel pump pressure was approximately 400 PSI when it should be approximately 700 PSI. I was told the fuel pump needs to be replaced. The vehicle is currently at the dealership awaiting the replacement part: Fuel pump I was not aware of a fuel-pump failure before the warning light appeared. I am particularly concerned because this failure occurred at only approximately 36,900 miles. GM previously recalled 3,386 2021 GMC Yukons under NHTSA Campaign 21V-739/GM Recall N212332040 for a fuel-pump power-control-module defect that can cause the fuel pump to fail or operate intermittently, interrupt fuel flow and potentially cause the engine to stall. My 2021 Yukon is not included in that recall and currently shows no unrepaired recalls associated with my VIN. I believe this represents a potential safety concern because inadequate fuel delivery or a fuel-system failure while driving could cause reduced engine power or an unexpected stall, increasing the risk of a crash. Given the low mileage, the dealer-confirmed fuel-pressure problem, and the existing fuel-pump-related safety recall affecting other 2021 Yukons, I am concerned that my vehicle may have the same or a related defect despite not being included in the recalled population. I believe NHTSA should evaluate whether additional 2021 Yukons should be included in a safety investigation or recall. I am paying out of pocket to have the fuel pump replaced and am filing this complaint to document the failure.A fuel-pump failure at only 36,900 miles is extremely concerning. I ask NHTSA to determine whether my vehicle has the same or a related defect and whether the existing recall population should be expanded.

NHTSA ID

11765898

Incident

Sep 21, 2026

I am filing this complaint regarding severe, excessive oil consumption in my 2021 GMC Yukon equipped with the 6.2L V8 engine (VIN: [XXX]). The vehicle is consuming oil at an accelerated and hazardous rate. Specifically, the engine oil level drops completely below the viewable crosshatches on the oil dipstick well before the vehicle’s automated Oil Life Monitoring system reaches 50%. This level of rapid oil depletion creates a significant safety risk, as it puts the vehicle at risk of sudden engine stalling, severe mechanical failure, or total engine lockup while driving at highway speeds, potentially causing a crash. General Motors has issued Safety Recall N252494000 to address internal manufacturing defects within the 6.2L engine that lead to mechanical damage and heavy oil loss. Although my vehicle is a 2021 model with the exact 6.2L V8 engine experiencing the identical, severe oil loss symptoms detailed in the recall, my specific VIN is currently excluded from the recall list. I request that the NHTSA investigate this issue and pressure General Motors to expand the parameters of Recall N252494000 to include all affected 6.2L engines exhibiting this dangerous defect. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11765877

Incident

Sep 17, 2026

The contact owns a 2021 GMC Yukon. The contact stated that while driving at various speeds on several occasions, the vehicle jerked and the transmission shifted hard into 1st and 2nd gears. The message "Service Safety Restraint" was displayed. The vehicle was taken to an independent mechanic, where it was diagnosed with a failed valve body. The contact was informed that the valve body or the transmission needed to be replaced. The manufacturer was notified of the failure. The failure mileage was approximately 88,000.

NHTSA ID

11764503

Incident

Aug 1, 2026

Mileage

88,000 mi

The contact owns a 2021 GMC Yukon. The contact stated that while his wife was driving 65 MPH on the highway at higher speeds, the vehicle shuddered abnormally. The check engine, ECU, and traction control warning lights illuminated, and the message "Shut off Vehicle as soon as Possible" was displayed. The contact's wife pulled over to the shoulder of the road, and the vehicle was towed to an independent mechanic for diagnosis. The mechanic retrieved dDTCs: P0307 and P050D, indicating a failed roller lifter, valve spring, and valve roller lifters. The vehicle was later towed to a local dealer, where the dealer diagnosed that the lifters had failed and needed to be replaced. The manufacturer was notified of the failure. The failure mileage was approximately 95,000.

NHTSA ID

11764399

Incident

Sep 12, 2026

Mileage

95,000 mi

Water is entering the passenger cabin through failed front sunroof drain tubes on both the left and right sides. The drains discharge inside the A pillars rather than to the exterior, pooling in the driver's side floorboard. An authorized GMC dealer diagnosed the cause in writing on August 12, 2026 as rubber grommet shrinkage and hardened internal buildup preventing water from flowing through, on both the left and right sides simultaneously. The identical bilateral failure mode indicates a component or assembly defect rather than debris blockage. Water is accumulating in the driver's footwell in proximity to cabin electrical components and the fuse block area, creating a risk of electrical shorting, connector corrosion, and circuit failure. Mold has developed in the front carpet and padding on the driver's side, and water intrusion staining is present on the passenger side. The dealer has quoted $2,727.16 to replace the drain tubes and the mold-damaged carpet and padding. The vehicle entered service on February 5, 2025 and has 45,211 miles. GM has issued service bulletin 20-NA-219 addressing sunroof drain hoses on 2021 Yukon, Yukon XL, Tahoe, Suburban, and Escalade models.

NHTSA ID

11763591

Incident

Aug 12, 2026