2025 GMC Sierra 1500 Problems: Engine (108 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.