2025 Gmc Sierra 1500 Engine Problems

Your engine's crankshaft has excessive end play (movement) that's outside manufacturer specifications, which a GM dealer diagnosed. You may notice excessive engine noise, but there were no warning lights before this issue appeared around 6,900 miles. This condition creates a high risk of engine failure while driving. The fix will likely require crankshaft inspection, bearing replacement, or potentially a complete engine overhaul or replacement.

Your 6.2L V8 engine seized while you were driving, after hearing pinging and knocking sounds. The engine shut off without warning and wouldn't restart—only cranking when you tried. Your dealer confirmed the engine needs to be replaced. This appears similar to previous GM recalls for the same engine.

Your truck displayed a "reduced acceleration" warning on the dashboard, which would disappear briefly when you restarted it but then return. Eventually, your truck shut off completely while you were driving, and when you tried to restart it, the dashboard went black and the engine wouldn't turn over. The dealership found multiple error codes and determined your engine needs to be replaced.

Your engine has stopped working twice since you bought the truck in June 2025. Both times, the dashboard showed a "loss of power" message and the engine wouldn't start, leaving you stranded during a family road trip and again after 5 months of ownership. The issue appears to involve the engine's electrical or fuel system failing to provide enough power to crank and start the engine.

While driving at highway speed, your engine suddenly lost most of its power and went into limp mode, forcing you to slowly exit the interstate with hazard lights on. The dealer diagnosed a failed thrust bearing in the 3.0-liter Duramax engine that requires a complete engine replacement according to GM's technical service bulletin. This type of failure creates a serious safety hazard on busy highways due to the sudden loss of power.

Your vehicle displayed a "Reduced acceleration; Drive with care" warning message at 5,200 miles, and the dealership found that a faulty thrust bearing caused complete engine failure. A faulty thrust bearing has caused catastrophic engine damage that makes your vehicle unsafe to drive, particularly when navigating traffic intersections. The dealership indicates this is becoming a more common issue with 2025 Sierras equipped with the 3.0 Duramax diesel engine, and GM's replacement engine supply is expected to take 2-3 months.

Your 2025 Sierra 1500 with the 6.2L engine makes a chirping, squeaking, or squealing noise when the engine restarts after auto stop and the transmission downshifts below 20 mph. GM says this is normal behavior related to their dynamic fuel management (DFM) system and ignition timing, but you've noticed this noise on your truck since it was brand new and haven't heard it on similar trucks. The noise could be coming from the engine's valve lifters and pushrods, or potentially from the transmission area. Fixing this may require valve train component replacement, transmission service, or a software update to engine timing.

Your 2025 GMC Sierra 1500 is making an abnormal knocking sound from the engine that gets worse when you turn on the A/C. Even after the dealer repaired a failed thermostat coolant housing, the knocking persisted. Additionally, your engine is consuming excessive oil—you need to add oil every 800 to 1,000 miles with no visible leaks underneath. A second dealer diagnosed a failed air compressor, which appears to be causing the A/C-related knocking. Fixing this will likely involve replacing the air compressor and investigating the excessive oil consumption.

Your vehicle has experienced multiple "reduced acceleration" warning alerts while driving, with your speed limited to 35 mph. The dealership found a P06DD diagnostic code indicating excessive crankshaft end play, which means the crankshaft thrust bearing is worn. According to the manufacturer's technical service bulletin, the engine will need to be replaced to resolve this issue.

I was traveling on the I70 West around the 210 mile marker. I was in the passing lane at high speed when the vehicle without warning switched itself off. The dash showed the “press start” warning, but the vehicle would not restart. I was fortunate that I was around 1/2 a mile from a rest stop area. I was able to glide the vehicle into the rest area. As I slowed close to a stop the vehicle suddenly stopped and applied the park brake. I am a very experienced driver, if my wife was driving, the vehicle shutting down completely in the fast lane could have been catastrophic. The road was busy. The vehicle was locked up in Park and was unrecoverable. It had to be dragged sideways out of the area that it had come to a stop, and then dragged onto and off the tow truck. The following morning the dealership confirmed the engine was seized. When I purchased the vehicle, the dealership confirmed that the historic failures on the L87 6.2L V8 engine were resolved. Clearly not the case.

Truck started with a knocking noise in the engine that developed into a grinding noise. Dealer Service Department inspected and did a transmission tear down only to discover the issue is with the excessive play in the crankshaft. At 13K miles, the service department has stated the entire engine needs to be replaced.

We were traveling when it went into limp mode slowing our speed way down. We got it to a dealership and they determined low oil pressure and metal in the oil. My vehicle only has 1185 miles on it.

I got 3200 miles on my 2025 gmc 1500 6.2 engine. The engine crash. Knocking. Skund like its going to jump out. Been at dealer in columbus. Since Thursday. No one touch it

The engine seized and locked up leading to a catastrophic failure of my three month old 2025 GMC Sierra Denali at approximately 3,181 miles. The engine, the 6.2L V8, was listed as a recall engine by GM for model years 2021-2024. My 2025 allegedly "passed inspection" yet had the same catastrophic failure. The vehicle engine made loud noises and it sounded like parts were breaking. The vehicle no longer starts and had to be taken via flatbed to the dealership where I was informed the engine had to be replaced.

- On 9/23/2025 while driving down the main street, the vehicle unexpectedly shut down (engine stopped running) and would not restart. The vehicle is currently at Elevation GMC (Boone ,NC) waiting to be diagnosed. - Safety was put at risk by the vehicle unexpectedly shutting down in the middle the of rush hour traffic and not being able to be moved. - When it is was towed into the dealership and explained to the service manager what happened; she said "there is a known problem with the gear select lever losing communication with the truck and not knowing what gear it is in". - As of 9/24/2025; dealership has not looked diagnosed what the problem is/was. - There were no prior warning messages before the engine shut down.

The contact owns a 2025 GMC Sierra 1500. The contact stated that while driving at an undisclosed speed, the vehicle experienced a loss of automotive power. No warning light was illuminated. The vehicle was towed to a local independent mechanic, where it was diagnosed and determined that the engine had seized and needed to be replaced. The local dealer was contacted. The vehicle was not diagnosed or repaired. In addition, the contact related the failure to an unknown recall; however, the VIN was not under recall. The manufacturer was made aware of the failure. The failure mileage was approximately 75,000.

The contact owns a 2025 GMC Sierra 1500. The contact stated that while at a stop light waiting to make a left turn, the vehicle stalled. The vehicle failed to restart. No warning lights were illuminated prior to the failure. The contact stated that the failure was related to NHTSA Campaign Number 25V274000 (Engine and Engine Cooling). The vehicle was towed to the local dealer to be diagnosed, and the contact was informed that the engine had seized. The vehicle was not repaired. The manufacturer was not notified of the failure. The failure mileage was approximately 21,100.

The vehicle was purchased for the express purpose of towing a 6,600 lbs Travel Trailer. This truck is equipt with the 3 liter Diesel engine. While towing the truck computer counts down milage available based on Def level. The count down is not mile for mile it is an exponential count down. This factor triggers a series of warnings concerning vehicle operation and impending speed restrictions. 1000 mile DEF range warning is first up. Followed shortly there after with a 300 mile DEF range warning (700 miles had never been reached to trigger the warning). The next warning is "DEF Low (red warning) speed restricted soon". Shortly there after a 500 mile count down starts for the first impending speed reduction to 65 MPH max. This is followed by other speed restrictions that will put the vehicle eventually into a 5 MPH speed restricted mode. When adding DEF to the tank the level has never been below 60% full. Its not empty as the gauge and computer indicate. With each filling of the DEF tank the range you can drive is less and less until the truck is driven without the trailer hooked up. GM has a service bulletin for this situation that has been in place since September 23, 2024 and no permanent repair of solution has been prescribed. During the 500 mile count down to the first speed restriction the instrument cluster is locked out to only display "DEF Empty" and alternately the DEF range counting down. No other safety features are visible such as engine temp or transmission temp important to know while towing. I Purchased this vehicle March 17, 2025 stating my intentions to tow a travel trailer. The dealership no GMC ever made me aware of the Service bulletin of the DEF restrictions. Had they done so I would have purchased a different vehicle with out the associated travel issues. Please reference GM Service Bulletin #24-NA-196 Document ID 6736285. This document was given to me after my 4 visit to a GMC dealership to have the issue addressed.

I WAS DRIVING ON A PA ROAD AT ABOUT 30 MPH. MY CAR STOPPED IMMEDIATELY AND I HEARD THE MOTOR REV. THE CAR THEN SLAMMED INTO A STOP.

Purchased the vehicle 300 miles away. Flew out, picked up the truck and drove it home. Got back Saturday night. Woke up Sunday morning to review the features, etc. Noticed a major oil leak. Called the dealership I purchased it from. They told me to take it to a (local) dealership. I took it to my local dealership. They looked at the vehicle. Initially they thought it was a faulty valve cover gasket. They ordered the parts. When they actually started taking the vehicle apart, the issue was not the valve gasket but the crack in the valve cover itself. They replaced the valve cover. It went to the dealer on date 03/03/2025 and they gave he vehicle back to me on 03/21/2025. They said this crack had to of happened on the production line but before it got delivered to the initial dealership.