GMC Complaints

My 2024 GMC Yukon Denali equipped with the 6.2L L87 V8 experienced an engine failure on July 4, 2026. Prior to the failure, there was no visible damage, warning, or other evidence that the engine was about to fail. I drove the vehicle to purchase fireworks and shut the vehicle off normally when I arrived. When I returned to the vehicle after shopping, the engine problem became apparent. There had been no noticeable indication of an engine failure before I turned the vehicle off. The vehicle was subsequently taken to a GM dealership, where the engine failure was confirmed and ultimately required replacement of the 6.2L L87 engine. The vehicle remained out of service from July 4, 2026, until it was returned to me on August 21, 2026. The original failed engine was in the possession of the servicing GM dealership I purchased the car from. Not even 8 months later of purchase the vehicle needed a 3rd engine (original, recalled engine, warranty engine). The lack of warning before the failure is a significant safety concern to me. The vehicle had been operating immediately before I parked it, and there were no apparent symptoms that would have alerted me that a major engine failure was imminent. Had the failure occurred while the vehicle was traveling at highway speed or in traffic, the sudden loss of engine operation could have created a dangerous situation. The failure was confirmed by the GM dealership and resulted in replacement of the L87 6.2L V8 engine. I am submitting this complaint to document the failure and because of continuing concerns regarding the L87 6.2L V8 and the effectiveness and long-term reliability of the recall remedy. I am still currently waiting for the repair work documentation for the new (assuming it was new) motor. I have attached attempts to talk to GM, app incidents, repair work being completed.

I am a Canadian owner of a 2023 GMC Sierra 1500 AT4 equipped with the 6.2L L87 engine. VIN: [XXX]. I purchased the vehicle new. I am reporting this because my experience appears directly relevant to NHTSA Engineering Analysis EA26005 concerning L87 engine failures after Recall 25V-274 remedies. The GM recall remedy/oil change was performed at 103,503 km (64,315 mi). At 130,695 km (81,210 mi), the original engine suffered a catastrophic failure and completely seized. The engine could not even be rotated manually at the crankshaft. GM replaced the complete engine. At 142,541 km (88,571 mi), only 11,846 km (7,361 mi) later, I returned for the first oil change on the replacement engine. I told the dealer that the vehicle was behaving abnormally, especially the transmission, which was shifting strangely. After inspection, the dealer determined that the replacement engine was beginning to seize. The increased resistance from the engine was causing the abnormal transmission behavior. The complete engine was replaced AGAIN. The vehicle now has 148,560 km (92,310 mi), meaning this second replacement/third engine has only about 6,019 km (3,740 mi). I am again noticing symptoms similar to those that occurred before the previous engine failure. I cannot confirm that this engine will fail, but after two previous engine failures, I am very concerned. This vehicle has therefore had two L87 engines: the original engine and one replacement. One replacement engine itself began seizing after less than 12,000 km. I believe these repeated failures after both the recall remedy and a complete engine replacement are directly relevant to EA26005 and the safety risk of sudden loss of propulsion. I have GM/dealer repair orders documenting the recall service and both engine replacements and can provide them upon request. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Driving on the highway lost proportion/acceleration, loud knocking coming from the engine

The lifters stuck and it ruined the cam shaft. This was repaired and then when driving home, the engine seized and started smoking. The engine was then diagnosed with complete failure and it had to be replaced. The engine had been upgraded a year or two earlier to the 0W-40.

Truck went into limo mode while driving and required valve in transmission to be replaced. Went from driving normal speed to only being able to go about 15 miles and hour. Was repaired got the truck back and the next day was on the interstate in the fast lane and the truck again had speed issue reduced speed and had to coast off interstate. This time entire valve body had to be replaced. Have gotten truck back and still have hard shifting in the transmission at times. Engine was checked for recall and now I have to pay a much higher oil change price due to a GM issue. This was not a known cost when purchasing this truck.

Complete engine failure, recall was performed before engine failed on highway with family inside.

Hello, I own a 2024 GMC Yukon Denali with the 6.2L V8. Car currently has 35,000 miles on it. At about 30,000 miles we started to feel a very aggressive vibration in the passanger seat, as well as the 2nd row seats, and driver seat. We took the vehicle in for the recall on the engine where we were instructed to put 0W-40 oil in. Much higher vescocity. After we did this recall the vehicle has not stopped shaking. We went for another service visit in July where we were told " this is the engine pistons trying to conserve fuel, and are firing causing the vibration." I have worked in the auto industry for 12 years, this is not a normal vibration. This should also not be caused by an engine. We then took it in again where they then proceeded to replace fuel manifold on August 18th. The vehicle shakes a bit less but still has a aggressive shake to it. I do not believe this is normal and if it is the engine pistons firing or the crank shafts misfiring, this could cause the engine to have catistrophic failure. This shake happens at speeds anywhere from 18 MPH to 50 MPH. My concern is with my wife and kids in this vehicle as the daily driver and this engine fails.

Driving down the interstate and lost all power, it said start engine and didn’t start coasted to the side of the road. It sounded like locked up engine, confirmed at dealership locked up engine.

Confirmed as catastrophic engine failure by dealership. New engine has been ordered.

Driving about 75 mph car shuttered and motor quit running had to pull off of the highway and get towed to dealership. Motor had to be replaced due to 1,2,6,7 rod bearings spun on the crankshaft. 34367 miles