GMC Sierra Complaints

15,732 consumer complaints on file.

#11760562August 29, 2026
ENGINE
FROM DEALER ASSESSMENT Concern - CUSTOMER STATES WHEN VEHICLE IS ACCELERATING THERE IS A RATTLE Correction - test drove and was able to duplicate rattle/knocking from the engine. checked oil level and condition verified both are good. checked for bulletins and followed 23-NA-170. compared vehicle noise to noise is video and noise is nearly identical. removed oil filter and inspected for debris, found heavy amounts of metal debris present in the filter. performed crankshaft end play mesasurement and found that the crankshaft end play is way over spec at 1/4 of an inch. recommend replacing the engine assembly per bulletin Parts) 1x ENGINE 2x (S)GASKET $0.00 $0.00 6x (S)BOLT 1x BOLT 1x exhaust pipe connector gaskets both sides $0.00 8x (S)GASKET 1x fuel feed pipes all $0.00 1x (S)SEAL KIT 1x (S)GASKET $0.00 1x (S)SEAL 1x W-(S)RADIATOR $0.00 1x (S)HOSE 1x coolant $0.00 1x oil filter 1x oil $0.00 Approved 2026-08-18 Labor: $0.00 Parts: $0.00 $0.00 $0.00 $0.00 $0.00 $0.00 $0.00 $0.00 Subtotal Line B: $0.00 *Subtotal is before Shop Charge and Taxes
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11760573August 29, 2026
WHEELS
The vehicle was delivered from the factory with a severe size mismatch between its primary rolling stock and its emergency spare tire. The truck features factory-installed 20-inch wheels and tires but was manufactured and shipped with an undersized 18-inch spare tire assembly secured underneath the bed. On a heavy-duty 3500-series truck built for heavy towing and hauling, utilizing a drastically different tire diameter during an emergency road event forces the rear differential and transfer case to spin at mismatched speeds. This creates an immediate risk of sudden mechanical drivetrain failure, loss of vehicle control, or compromised braking stability while operating under load on public highways. Consumers relying on factory equipment during emergency roadside scenarios should not be exposed to hidden mechanical hazards due to factory assembly omissions. Upon discovering the factory defect, the local dealership attempted remediation by supplying a shop take-off wheel and an aged, three-year-old tire (DOT 2223). This highlights that while individual dealerships scramble to fix these factory omissions with makeshift inventory, consumers purchasing new heavy-duty vehicles are still absorbing compromised, aged safety equipment due to lack of manufacturing quality control. I have also filed a complaint with GM and have requested immediate remediation with a correct new tire and wheel and am waiting for a response.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11760574August 29, 2026
WHEELS
The vehicle was delivered from the factory with a severe size mismatch between its primary rolling stock and its emergency spare tire. The truck features factory-installed 20-inch wheels and tires but was manufactured and shipped with an undersized 18-inch spare tire assembly secured underneath the bed. On a heavy-duty 3500-series truck built for heavy towing and hauling, utilizing a drastically different tire diameter during an emergency road event forces the rear differential and transfer case to spin at mismatched speeds. This creates an immediate risk of sudden mechanical drivetrain failure, loss of vehicle control, or compromised braking stability while operating under load on public highways. Consumers relying on factory equipment during emergency roadside scenarios should not be exposed to hidden mechanical hazards due to factory assembly omissions. Upon discovering the factory defect, the local dealership attempted remediation by supplying a shop take-off wheel and an aged, three-year-old tire (DOT 2223). This highlights that while individual dealerships scramble to fix these factory omissions with makeshift inventory, consumers purchasing new heavy-duty vehicles are still absorbing compromised, aged safety equipment due to lack of manufacturing quality control. I have also filed a complaint with GM and have requested immediate remediation with a correct new tire and wheel and am waiting for a response.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11760587August 29, 2026
ENGINE, POWER TRAIN, UNKNOWN OR OTHER
ENGINE STARTED KNOCKING AT 18K MILES AND TOOK TO DEALER AND THEY FOUND METAL IN THE FILTER AND INSTALLED A NEW ENGINE AND ALSO REPLACED THE MIDPLATE GASKET ON THE VALVEBODY DUE TO A HARSH DOWNSHIFT WITHOUT CODES IN THE SYSTEM THIS ENGINE IS GOING ON 2K MILES AND IT SEEMS TO BE FINE NOW BUT THE PROBLEM WITH 6.2 WAS ONLY SUPPOSED TO BE ON THE 21-24 MODELS AND MINE IS A 25 MODEL AND ALREADY HAD A REPLACED AND NOTHING FROM GM WAS SAID TO EXTEND THE WARRANTY ON THIS MODEL AND POWERTRAIN
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11760597August 29, 2026
ENGINE
Driving approximately 75mph on a local highway, my engine shut down with no warning, the screen said to shift into neutral to restart but nothing happened so I was stranded along the side of the highway and had to wait 2hrs for a tow truck in the middle of the night and the engine is currently locked up.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11760628August 29, 2026
ENGINE
Engine making noise during a trip took to dealership and they reported engine is bad and needs to be replaced because it would freeze on the road. Vehicle has 7000 miles.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11760654August 29, 2026
ELECTRICAL SYSTEM, ENGINE, EXTERIOR LIGHTING
1 - The Engine or something electrical, possibly the ECM, failed or malfunctioned, and yes, it is available for inspection. 2 - The vehicle lost power, reduced speed, was hard to steer, and I couldn't put the hazard lights on; this occurred twice while driving on the highway, once I was driving at approx 75 mph. The results could have been catastrophic not only to myself but to others on the road. These two events are not the only times the truck did this. 3 - No. 4 - No. I filed a claim with GM, but it has been approximately a month, and I've received no updates. 5 - No. Further: This event has occurred 6 times. I've taken it to the dealership three. They cannot duplicate the issue, so no repairs have been done. Apparently, approximately 100 codes come up, but they cannot diagnose the problem.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11760660August 29, 2026
ENGINE
Early this year the crankshaft seized while driving. The engine was promptly replaced and I carried on my way. Then 7k miles later, the replacement engine that GM sent also blew up and was a total replacement. Hopefully the third engine lasts longer.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11760197August 28, 2026
ENGINE, POWER TRAIN, VEHICLE SPEED CONTROL
I own a 2025 GMC Sierra 1500 Denali equipped with the 6.2L V8 L87 engine, VIN [XXX]. The vehicle had approximately 35,000 miles when the engine experienced a catastrophic engine failure. Prior to/during the failure, the vehicle experienced abnormal engine noise and a loss of power. Multiple warning/alarm lights appeared on the dashboard, including the Check Engine and Traction Control warning lights. The engine failure resulted in a loss of motive power and made the vehicle unsafe to operate. PHONE# [XXX] The sudden loss of engine power while driving created a serious safety hazard because the vehicle could no longer operate normally in traffic and could potentially cause a crash. I am requesting that NHTSA document and investigate this engine failure as a potential safety defect involving the GM 6.2L L87 engine. I am also requesting that NHTSA determine whether 2025 GMC Sierra 1500 vehicles equipped with this engine should be included in an appropriate safety recall or other corrective action. The vehicle is a 2025 GMC Sierra 1500 Denali with approximately 35,000 miles. The engine failure and warning lights occurred during normal vehicle operation. The vehicle and repair records can be made available for inspection, and I can provide dealer repair orders, diagnostic information, photographs, and other documentation concerning the failure. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11760208August 28, 2026
ENGINE
I had an engine rebuilt completed on my L86 2017 GMC 6.2. After the repair, the engine failed due to the crank shaft on the engine being oversized which is the same problem that GM is having with the L87 engines. When the crank was ordered from the dealer for my L86, the only part number for the crank that was available was the new part number that was being used in the L87. Seems the same cranks were used in both engines and this recall on the L87 should be extended to anyone that had a rebuilt complete. Me and my family were left on the side of the road for a few hours which endangered our lives. The problem was determined by an independent service center and was fixed by the purchase of new parts and aftermarket bearings for the crank to allow the oil to enter the crank properly. There were no warning signs. Was driving down the road, started to hear a noise and then the engine started to over heat so that is when I stopped and called a wrecker.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11760218August 28, 2026
ENGINE
My vehicle is on a recall list. Took it to the dealership for engine vibration test. They changed oil and put on a new cap. My engine blew up a couple weeks later. They replaced my motor. It blew up on the mechanics test drive. I'm now waiting on my 3rd motor. They have had it for over 5 months now.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11760220August 28, 2026
ENGINE
While driving through city traffic at approximately 35 mph the truck engine made a quick loud noise and then immediately shutoff. The power steering went out and then I was unable to pull off the road completely as the engine would not start back up. This truck is a 2026 with 9,000 miles, 6.2L motor. After being towed to a GM Service facility it was determined that the motor had blown up on the truck. A vehicle shutting off while driving down the road is an extreme safety concern in my opinion.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11760243August 28, 2026
UNKNOWN OR OTHER
Learned that GMC engines may have an issue. We haven't had one as yet.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11760249August 28, 2026
ENGINE
2021 GMC Sierra 1500 equipped with 6.2L L87 engine. At approximately 97,000 miles, the engine developed a significant knocking noise. I immediately took the vehicle to an authorized GMC dealership for diagnosis. The dealer determined that the engine required replacement but advised that my VIN was not included in GM Recall 25V-274. The dealer quoted approximately $15,000 for replacement. I subsequently had an independent repair facility replace the failed engine with a genuine GM replacement engine at a cost of approximately $12,400. I am reporting this because the failure appears similar to the L87 engine bearing/crankshaft failures addressed by Recall 25V-274, despite my VIN not being included in that recall.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11760250August 28, 2026
ENGINE
I had the L87 recall completed, and the vehicle passed inspection. The dealership completed the required protocol and replaced the engine oil with 0W-40. Approximately 6,000 miles later, while traveling at about 75 mph and six hours from home, I experienced a brief loss of power followed by an immediate return of power. My wife and I noticed it but, with no warning lights or alerts, continued driving while monitoring the vehicle. About 10 miles later, we began hearing a faint squealing noise that progressively became worse. I was able to exit the highway safely, but once I came to a complete stop, the engine shut off and would not restart. I had the vehicle towed to the nearest dealership, where it was determined that I had suffered a catastrophic engine failure. No loaner vehicle was available, leaving my family stranded six hours from home with an inoperable vehicle. It took approximately seven to eight weeks for the repair to be completed. When I received the vehicle back, I immediately noticed something still was not right. At around 40 mph and 1,000 RPM, the truck would shudder or hesitate. My local dealership diagnosed a poor spark plug connection on cylinder #3, which was causing arcing and a misfire. After the connection was repaired, the issue was resolved. My local dealership is currently working with the repairing dealership to address several minor workmanship issues, including wire clips, fittings, and missing bolts. This entire event was unexpected. There were no warning lights, alerts, or unusual noises before the initial loss of power. The only indication of a problem was the sudden power loss followed shortly thereafter by a horrific screeching noise. Thankfully, I was able to safely exit the highway and bring the vehicle to a stop. Considering I was traveling at 75 mph, the situation could have been much worse.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11760257August 28, 2026
ENGINE, FUEL/PROPULSION SYSTEM, POWER TRAIN
I am the owner of a 2019 GMC Sierra 1500 4WD equipped with the 6.2L L87 V8, VIN [XXX], currently at 177,271 miles. On [ADD DATE] while driving 40-45 mph westbound on [XXX] near XXX in [XXX], in a school zone, the engine suffered sudden catastrophic internal failure with complete loss of propulsion and would not restart. No prior warning lights or low oil pressure warning. Vehicle required tow from school zone. GMC dealer inspected and verified catastrophic internal failure. Dealer stated verbally failure is either camshaft broken in half or timing chain sprocket/pulley broken off or loose causing timing chain to come off. Timing cover was not removed to confirm. Dealer stated engine is not repairable and quoted $13,500 for new engine replacement only. I have copies of the work order and the dealer's written statement verifying internal failure and replacement recommendation. Engine and vehicle have been retained. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11760298August 28, 2026
ENGINE, ENGINE AND ENGINE COOLING
The contact owns a 2021 GMC Sierra 1500. The contact stated that while driving at 60 MPH, the vehicle began to shake uncontrollably. A knocking sound was heard from the engine, and the vehicle entered limp mode. No warning lights illuminated. The contact was able to coast the vehicle to the residence. The vehicle was later towed to the dealer, where it was diagnosed that the engine failed and needed to be replaced. The contact associated the failure with NHTSA Campaign Number: 25V274000 (Engine and Engine Cooling). The vehicle was not repaired. The manufacturer was notified of the failure and informed the contact that the VIN was not included in the recall, and the contact was advised to file a complaint with the NHTSA Hotline. The failure mileage was 81,000.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11760306August 28, 2026
ENGINE
I purchased a new 2024 GMC Sierra. I brought it to the dealer for the engine recall on the 6.2liter. It passed the inspection and the oil was changed to a heavier weight. After the recall was satisfied and the oil was changed to the heavier weight, around 45,000 miles, the engine failed at highway speeds while pulling a trailer and left my entire family stranded on the side of the highway; late at night. The engine completely failed and would not re-start. After researching the issue online and watching mechanics tear down these engines and suggest the problem, I believe that GMC has created great harm to the customers who've purchased the vehicles with 6.2L engines by allowing us to drive hundreds of thousands of "ticking time-bombs" across the country. Furthermore, it is absolutely infuriating to learn that problems clearly identifiable starting in 2021 were not addressed until a recall in April 2025. I strongly believe that G.M. has mishandled this information and put customers into vehicles that are verifiably unreliable and should correct the problem/take the hit to replace these faulty engines. !!TIMEBOMBS!! [XXX] [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11760336August 28, 2026
POWER TRAIN
Rear wheel lock up. Very unsafe. I am on my 3rd valve body for my transmission. GM doesn’t want to replace transmission but will warranty for 150k miles. I bumped a semi during one of my lock ups.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11760415August 28, 2026
ELECTRICAL SYSTEM, ENGINE, FUEL/PROPULSION SYSTEM
13 unresolved problem codes relating to hard engine starting,rough engine running,vehicle initiating safe mode operation, upon a highway trip. P0016 engine code detected and Onstar messaged for immediate service. No resolution at dealership , after resetting codes an additional 9 are active / pending at 2nd dealership visit. Abnormal engine operation since , dealership advises a hard failure has to occur before a resolution can be instituted. Similar advice from GMC direct phone call in help line.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0

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