2025 GMC SIERRA 1500 Complaints

So I spent many months trying to aquire a GMC Sierra Denali and with all the issues with the 20 - 24 6.2 engines we were assured by the dealer that all the issues were resolved with the 2025 6.2 models. So we spent big to aquire an 2025. So I bought one new. My truck had 8000 miles on it with 2 oil changes. So we booked a trip to [XXX] at considerably a large expense and loaded up our Harley's on my light aluminum trailer, less than 3.5k pounds and headed that way from [XXX]. We made it to [XXX] and spent the night. Next morning we were heading to [XXX] and the truck blew up on the XXX. We were pulled over on a very busy hi way and had to get truck and trailer towed back to [XXX]. We were stuck there for 3 days while GMC installed a rebuilt motor in my 83k truck and totally missed our entire vacation. On line it said GMC would cover hotel and 40.00 dollars a day food. I am so disgusted after being reassured that GMC had fixed the 6.2 and putting our life in danger blowing up on a major highway, and afterward GMC only gave us 200. For our inconvenience. Our room alone was more not counting the money lost on out trip accommodations. I am so completely disappointed with this truck that we bought new and spent more than we ever had on a vehicle, and am afraid of ever taking another trip in it. How can GM be allowed to do this to people. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Safety Complaint – 2025 GMC Sierra 1500 Tailgate While driving our 2025 GMC Sierra 1500 and towing a trailer, the tailgate unexpectedly opened and dropped down while the vehicle was in motion. No one touched the tailgate button, key fob, or any other controls to activate the tailgate. We were unaware that the tailgate had opened. When we made a turn, the trailer contacted the tailgate and crushed/damaged it. This occurred without any intentional activation of the tailgate release. We believe this presents a significant safety concern because an unexpectedly opening tailgate while driving, especially while towing a trailer, could result in property damage, loss of cargo, or a more serious accident. We are requesting that this issue be investigated to determine whether there is a defect with the tailgate latch, release mechanism, or electronic controls on the 2025 GMC Sierra 1500.

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.

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

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

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

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)

I pulled up to a local store and parked. Just as I was getting out I saw smoke coming from the upper seatbelt area of the rear drivers side seat inside the cab. I jumped in back to see if there was a fire. As I was trying to pull out the top cushions of the interior roof, trying to locate a possible fire, the rear driver-side window suddenly "exploded" - broke in a web pattern across the entire window. I then broke out the center of the glass in case a fire started. I could smell a burning scent. The, suddenly the rear passenger-side window exploded in the same web pattern across that entire window. When my wife arrived to pick me up she could also smell the scent of burning wire. After researching the internet for this issue, we found out that this is a known issue. We discovered at least 6 websites describing this exact issue - one being a GM Customer Satisfaction Program #N192265660 dated January 2020. Apparently the component that has been determined to have failed is the rear window defrost (particularly in models with an electronic sliding rear center window) overheats and causes the smoke and the window breakage. After our truck being at the dealership for approximately 1 month while GMAC supposedly researched the issue, we received word today verbally (Aug 27, 2026) that they declare this issue is not a manufacturer's defect, and they will not cover the repairs. We have requested written confirmation and haven't yet received it. Not only do we currently have the original warranty on this vehicle, we also purchased the extended warranty for the vehicle. The vehicle was inspected by the dealership from which we purchased the vehicle and they stated they couldn't find any issue that would create the damages that the vehicle incurred. Prior to the incident there were no warning lamps or symptoms of any problem.

Engine shut off. It did restart after placing it in park. I did own a 2022 Sierra Denali and the motor failed on that vehicle. I swapped out to the 2025 to get away from what I thought was a problem on that vehicle and now learning this is an inherent problem with the 6.2L motors that include this year. As a consumer, I am very infuriated that the problem has been in place for years and still is today. The DOD system in these motors is also a problem and will eventually rear it's head out of warranty. You can go purchase a DOD delete kit and pay someone to remove and install the kit but at an additional 2500 in expense for parts and labor. This needs to be addressed!

The 2025 GMC Sierra 1500 with 18,675 miles and the 6.2 gas engine failed during a road trip. I was on my way from [XXX] to [XXX] on the Interstate when about 7 hours in, just outside [XXX]. I was noticing a lack in power when I pulled out of a rest area. The truck would not accelerate over 60mph. I slowed down and as I was pulling off the side of the interstate, the truck died. There was knocking sound as I started to pull over. I attempted to restart the vehicle; it did not restart. I called roadside assistance and the tow truck to myself and the truck into Edwards Chevrolet Cadillac in [XXX]. They diagnosed the issue as spun or bad bearing in the engine, and it would need replaced. They told me that the last 6.2 engine took 60+ days to receive and they were now on backorder, plus they already had a truck in the shop waiting for one. There were no warning indicators on the console, and all my service has been done at GM dealers. The biggest safety issue was being stuck on the side of the interstate with rushing semi's going by. I was also going to be stuck in [XXX] until a resolution was found. I ended up purchasing a new 2026 GMC Denali Ultimate with the 3.0 diesel. It was the closest package that was on my 2025 and I wanted to stay the same, minus the 6.2 engine. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)