GMC Complaints

The engine needs replaced and GM doesn't have any engines or know when we will get any engines. Evidently this affects numerous 6.2 liter engines that GM made from 2021-2024.

Engine power reduced, could not accelerate, fuel pump issue and was bucking the engine Went to dealer and complained as gmc not working to help me, dealer fixed issue but said no other complaints out there and car was fixed, gmc called me several times and keeps saying no issues with the vin associated. The car was fixed but I am stuck with a truck that is probably not saleable once these issues continue. This issue happened initially with 30 k on it and dealer could not find the issue and this times at 61500 happened again

2023 GMC 1500 Sierra Denali Ultimate tailgate opens without being commanded. This has happened approximately three (3 ) times in the last two months while being driven with the most recent incident occurring today, 04/27/2025. There are no warning lights indicating when a tailgate opens while the vehicle is being driven.

1st time - rear main seal blew out & engine lost all of its oil causing rocker arm to break & chains to slip-vehicle sputtered & DIED while driving down busy street & would not restart - my safety & safety of others driving behind me were at risk for causing a rear end accident and/or pile up crash - no warning lights or sounds alerted me - dealership told us General Motors is aware this is/has been a problem with 2017 Terrain vehicles especially those driven in Midwest states due to colder temperatures - the intake manifold vent hole is not large enough to let air out, so it plugs up & causes pressure to blow out rear seal, which causes oil to leak out and engine dies. When replaced with a remanufactured engine intake manifold vent hole was not drilled out causing it to happen again 2nd time - when leaving parking spot at work noticed oil puddles underneath my vehicle, I checked my oil, it showed full, I was concerned, drove to nearby last place I got my oil change. They informed me that all the oil had leaked out and showed me the bottom of my vehicle oil covered the front to the back of my vehicle. They also said that I was extremely lucky to get to shop before engine blew and stopped dead. AGAIN my safety and safety of others behind me could have been a rear end accident and/or car pileup crash - again no warning lights or sounds alerted me - shop personal told me General Motors is aware this is/has been a problem with 2017 Terrain vehicles especially those driven in Midwest states due to colder temperatures - even though the repairs where done by a certified dealership the first time they replaced with a remanufactured engine but failed to drill out the intake manifold vent hole bigger so this would not happen again BUT IT DID. General Motors cannot just sell vehicles it has to stand behind what they sell which in my case they have not. Due to GM lack of concern, recalls, reimbursements, lives have been and continue to be at risk

Rear sliding glass window is leaking water around the exterior frame. This is addressed in TSB 18-NA-383 but not covered under any warranty. My rear seats and carpet are becoming wet. I am concerned about the possibility of mold and an electrical short/fire resulting from water intrusion. There are many reports and discussions on the internet regarding this issue. Full window replacement estimated at $1300. Patchwork repair with caulk is estimated at $600 with no guarantees of success. I would expect GMC to cover the replacement of the rear glass in kind and remedy any other damage to my vehicle due to water intrusion into the cabin area.

Breaks went out on vehicle with no warning or lights on dash. Nothing prior or now indicating any issues with breaking system.

While driving on a busy highway, the engine stalled and could not be restarted. We were in the left lane and thankfully traffic was light and i was able to get to the shoulder. No warning and no check engine light before stall. After numerous attempts and about 15 minutes it did restart. A few miles later same issue and could not restart. We were 200 miles from home. Called GM and they sent a tow truck. Dealer had the car for almost a month and replaced the engine because they found metal in the oil and determined that the main bearings had spun. The concern is that the replacement engine is presumably a 2024 and the issue could happen again.

I bought this truck new in March 2015 there was a recall for the steering shortly after which I had done, everything was ok for three years. Then I had power steering failure. After shutting off and everything is normal, until it happens again. It is now 10 years old and it has hapened 7 times in 10 years. there is no pattern to the occurrences.

While driving without any warning the screen said press start. The vehicle shifted to neutral and lost all power while driving down a very busy road on the top of a hill going 55 mph. Once stopped we tried to turn the vehicle back on, vehicle would power on but wouldn’t start just click and screens flash

While driving, the check engine light started to blink and there was a steady knocking coming from the engine. This is the same issues that GMC is currently recalling newer model vehicles for. Safety was at risk because the engine failure happened while driving.