2021 GMC Yukon: engine failure

Filed Oct 28, 2026 · Fuel system · NC

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.

Filed Oct 20, 2026 · Engine, Transmission · PA

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 the federal safety agency 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)

Filed Oct 16, 2026 · Engine, Transmission · GA

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).

Filed Sep 26, 2026 · Engine · TX

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.

Filed Sep 11, 2026 · Driver assistance, Engine · TX

Crankshaft / Camshaft caused catastrophic engine failure while on a family road trip leaving family and kids stranded on the side of the highway for hours. 2021 GMCs are notoriously having this issue but they refused to include our VIN in the recall. It cost us almost $13,000 to replace with a brand new engine and only 4 days after picking up from dealership the vehicle stopped working and shut off at a light in the middle of the road. GMC has been no help and won’t cover anything.

Filed Sep 3, 2026 · Engine · MS

My 2021 GMC Yukon began experiencing severe engine problems, including shaking/rough running, a noticeable ticking/knocking noise from the engine, and a flashing check-engine light. The vehicle also displayed Service ESC and traction control warnings and exhibited symptoms of an engine misfire. I took the vehicle to a dealership for evaluation. I was advised that the problem may involve failed lifters and that the vehicle could be out of service for several weeks for repairs. I was also advised that the repair could be very costly. At this time, I have not been given a final diagnosis, so the exact internal engine component responsible for the failure is UNKNOWN. I am concerned that the condition presents a safety risk because the engine is running extremely rough and the check-engine light is flashing. I am afraid the engine could lose power or fail while the vehicle is being driven, potentially putting me, my passengers, and other motorists at risk. I have also become aware of the federal safety agency's investigation involving failures of the 6.2-liter L87 V8 engine in GM vehicles, including the GMC Yukon, as well as reports of engine failures occurring after certain repairs or recall remedies. This has increased my concern about whether repairing or replacing individual engine components will permanently resolve the problem. I am submitting this complaint so that my vehicle's symptoms, dealer evaluation, and potential engine failure are documented. The vehicle and affected components are available for inspection upon request. The dealership has evaluated the vehicle, but a final determination of the exact cause has not yet been provided.

Filed Sep 2, 2026 · Engine · PA

While driving my 2021 GMC Yukon Denali with the 6.2L L87 V8 on a high-speed highway near Somers Point, New Jersey, the vehicle suddenly began bucking and the accelerator stopped responding normally. The vehicle rapidly lost propulsion while I was surrounded by highway traffic and approaching a bridge. I was fortunate to get the vehicle onto the shoulder before reaching the bridge. I was then stranded on the shoulder of a high-speed highway, where the disabled vehicle created a serious safety risk to me and other motorists. The engine shut down and would not restart. It initially cranked as though it was attempting to start, but it did not start. I received a diagnostic alert stating, “Service the engine and transmission system immediately.” The vehicle required a tow. The tow operator later reported that it appeared locked up and could not be shifted into neutral. The vehicle has approximately 77,000 miles and has been serviced regularly. Its most recent oil-change sticker indicated the next oil service was due at approximately 81,000 miles. While safely pulled over, I checked the engine-oil dipstick and confirmed that the engine had oil, with oil visible across the dipstick’s normal measuring area. Despite this vehicle having the 6.2L L87 engine and experiencing a sudden loss of propulsion and no-start condition, its VIN does not currently appear in GM’s public recall lookup for the existing L87 recall. The vehicle is being transported to an authorized GMC dealer, and the precise failed component has not yet been confirmed. This sudden loss of propulsion created an immediate risk of a serious highway collision, particularly because it occurred immediately before a bridge. I understand the federal safety agency is investigating continuing L87 engine failures, including failures involving vehicles outside the original recall population. I am submitting this complaint so this incident is formally documented and considered as part of that investigation.

Filed Sep 1, 2026 · Engine · TX

My 2021 GMC Yukon Denali with approximately 88,000 miles developed a significant engine knocking noise and was towed to a GMC dealership for diagnosis. The dealership confirmed diagnostic trouble code P0301 (engine misfire) and documented a “knocking noise in lower end at piston rod crankshaft area.” The dealership advised that my vehicle is not currently included in the existing GM recall for certain 6.2L L87 engines. The vehicle has the 6.2L L87 V8 engine. I am concerned because the documented knocking is located in the lower engine area involving the piston/connecting rod/crankshaft area, which is consistent with the type of internal engine failure associated with the L87 engine investigation and recall. I am concerned about the possibility of sudden engine failure and loss of propulsion while driving. I am requesting that the federal safety agency investigate this failure and consider whether vehicles outside the current recall population should also be included. I also recently experienced an engine replacement on another 2024 GMC vehicle. I am providing that information as additional customer experience, but I am not claiming that the two failures are necessarily caused by the same defect.

Filed Aug 30, 2026 · Engine · AK

Was taken in for recall at 74,000 they put on a new oil fill cap, did oil change and had catastrophic engine failure at 77,000 miles. Engine replaced by dealership.

Filed Aug 29, 2026 · Engine · NC

I’m currently on my third motor as a result of the L87 engine loss. When I bought the vehicle, I was not aware that the engine had already been replaced however, due to hearing a tick, I brought my vehicle to the dealership for the recall and was told that this is not the original engine, but they had the paperwork for this engine as well. Nonetheless, the engine “passed” their inspection. They changed my oil and replaced my cap. Within six months, I threw a Rod. Not only did I have a horrible experience with the dealership, my new motor is also ticking.

Filed Aug 27, 2026 · Engine · 151,017 miles · GA

The contact owns a 2021 GMC Yukon. The contact stated that while driving at 70 MPH with family members in the vehicle, the transmission independently shifted into neutral. No warning lights illuminated. The contact was able to steer the vehicle into a residential driveway, where the vehicle failed to restart. The contact requested towing services; however, the initial tow driver failed to arrive after nearly three hours, requiring the contact to call a second tow company. The vehicle was towed to a dealer, where it was diagnosed with engine failure, and it was determined that the engine needed replacement. The vehicle was not repaired, but replacement parts were ordered. The contact associated the failure with the federal safety agency Campaign Number: 25V274000 (Engine and Engine Cooling). The contact stated that in January 2026, the vehicle was taken to the dealer for the recall repair, but the contact was informed that the vehicle had passed the recall inspection. The manufacturer was notified of the failure, and a case was opened. The manufacturer offered a 90% discount on the repair costs; however, the contact declined the offer and requested a full refund for both towing service fees. The failure mileage was approximately 151,017.

Filed Aug 27, 2026 · Engine · TX

Once we learned about the 6.2L Engine Failure we took the vehicle to Mckinney GMC in [XXX], test were run and were told the engine needed to be replaced, but would take several months to repair. We could not wait months for the vehicle so we had the vehicle towed to Sewell GMC in [XXX] (we bought the vehicle CPO from there) they ran test and said we didn't need a new engine but that they would just replace the oil weight and it would be fine. The engine has not run right since, it shakes and idles hard, and was never given a clear answer as to how metal shavings were found in the oil at McKinney GMC but magically disappeared at the Sewell dealership. Its very unsettling that at any moment while driving the engine could seize and blow. I feel like we have a lemon vehicle and the oil weight change is simply a band aid for this situation. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)