Which parts fail
Components named in complaints (engine, cooling system, oil leaks, timing chain, exhaust).
Mileage when the problem started
Owner reports
Selected complaints filed with NHTSA by 2021 GMC Acadia owners, lightly cleaned up (personal details are redacted by NHTSA).
The contact owns a 2021 GMC Acadia. The contact stated that while driving at an undisclosed speed, the check engine warning light illuminated. In addition, the coolant fan was running after the engine was turned off. The vehicle was taken to Auto Zone to be diagnosed due to the check engine warning light being illuminated. The contact was informed that DTC: P1098; was retrieved, which indicated a fault with the coolant control valve. The vehicle was taken to the dealer, where it was confirmed that the coolant control valve had failed. The vehicle remained at the dealer unrepaired. The contact related the failure to the Manufacturer Recall Number: N252508341. However, the VIN was not included in the recall. The manufacturer was made aware of the failure and advised that the VIN was not under recall. The failure mileage was approximately 69,000.
The contact owns a 2021 GMC Acadia. The contact stated while stopped at a stop light and depressing the brake pedal, the engine revved up with the RPM's increasing up to 15,000. No warning lights were illuminated. The contact stated that the vehicle jerked and vibrated as the transmission did a hard shift. The vehicle was taken to the dealer who took the vehicle on a 24-minute test drive and no failure was found. The vehicle was taken to the dealer several times and no failure was able to be determined. The failure occurred several times. The manufacturer was notified of the failure however, no assistance was offered. The approximate failure mileage was 249.
The contact owns a 2021 GMC Acadia. The contact stated while driving at an undisclosed speed, the check engine warning light illuminated and DTC: P04FB; was displayed. The vehicle was taken to the dealer where it was diagnosed with moisture of the crank case. The vehicle was repaired. The contact stated that the failure was a quick fix and was covered under the warranty. The contact stated that the failure had occurred several times and was covered under warranty. The contact was informed that there was no fix for the failure. The manufacturer was not made aware of the failure. The failure mileage was approximately 37,000.
The contact owns a 2021 GMC Acadia. The contact stated that while his wife was driving at an undisclosed speed, the vehicle inadvertently lost motive power. The driver was able to coast to the shoulder of the roadway, where the vehicle failed to restart. The check engine warning light was illuminated. The vehicle was towed to an independent mechanic, who diagnosed a failure with the fuel pump control module. The vehicle was repaired. The manufacturer was notified of the failure but provided no assistance. The failure mileage was 36,970.
The contact owns a 2021 GMC Acadia. The contact stated that while driving, he heard a loud rattling noise coming from the exhaust. The contact then stated that the RPM's increased and the rattling noise became louder. No warning light was illuminated. The vehicle was taken to the dealer where it was diagnosed that the exhaust resonator failed the whole exhaust assembly needed to be replaced. The vehicle was not repaired. The manufacturer was not notified of the failure. The failure mileage was approximately 28,000.
While driving vehicle stalled multiple times in the middle of the road, with service transmission and engine light coming on, causing unsafe conditions, causing accident and leaving passengers stranded. Battery being drained and needing to be replaced multiple times within 2 years. Vehicle stopping and shutting off on the highway causing dangerous driving conditions!! Radio and lights flickering, with radio freezing and shutting off. Electrical system not working properly and overheating!
The contact owns a 2021 GMC Acadia. The contact stated that after a routine maintenance at the local dealer, it was noticed that the radiator was leaking coolant. Upon further inspection, the contact and his son noticed that the driver's side of the radiator was corroded. No warning light was illuminated. The vehicle was not repaired due to the cost. The manufacturer was made aware of the failure. The failure mileage was approximately 32,175.
I got into an accident because my back up crap camera did not warn me that a car had turned behind me. Also when and backing up and a car is coming it doesn't indicate the car is coming until it's behind me. I've taken it to the dealer and they say there's nothing wrong with it. Also there is no break when you come too close to something in front of you.
May 2023 we took the car to the GM dealership for a electronic recall. We reported a rattling noise at that point in time. Whatever repair was done that the car ran w/o any noise for nearly a year. April 2024 the catalytic converter failed at just 61K miles on this vehicle. The mechanic at the same dealership noted a broken mounting bracket and replaced the catalytic converter. October 24 2024 at 76K miles the car started making the same noise. The mechanic at the same dealership noted a loose mounting bracket due to an excessively vibrating catalytic converter, a crack on the cat converter, a leak and sequentially damaged front pipe. They noted they made all of those repairs. They noted they test drove the vehicle and verified the car was repaired. October 26, 2024 after those final repairs the car made a loud revving noise and emitted a smell of sulfur. …
car had only 5000 MILES . We live in denver took it to mountains for first time. we are both in our late 70 s . going down mouintains vail pass car engine EXPLODED CAR WENT INTO COMPLETE stop at highway speed. LUCKY WE DID NOT DIE as car went off to berm on i 70 west. milemarker 180 OR SO. GMC roadside called after 18 hours finally consented to tow car back to denver. we called 911 FOR FEAR OF OUR LIFE with trucks wheezing by. " GMC national" would not buy back car. my wife and I explained to gmc we were in a panic when this happened. DEALER AUTO NATION FOUND THAT pistons were blown up as well as engine. THEY OFFERED to give us new ?REBUILT engine .. we refused as we are very frightened to be in this car. DEALERSHIP FINALLY offered to buy car which we consented . …
Engine complaints in other Acadia years
Frequently asked questions
How common are engine problems on the 2021 GMC Acadia?
NHTSA has 31 complaints about the engine & cooling of the 2021 GMC Acadia, 20% of the model year's 154 complaints. The component named most often is exhaust system › emission control (1 mentions).
Is there a recall for 2021 GMC Acadia engine problems?
No. NHTSA lists no engine & cooling recall for the 2021 GMC Acadia, though it has 2 recalls for other components. If the problem is widespread, a repair may still be covered by an extended warranty or a manufacturer service bulletin — ask a dealer.
At what mileage do 2021 GMC Acadia engine problems start?
Half of the complaints with a recorded mileage happened before about 37,000 miles, and 17% before 25,000 miles.
Is it dangerous?
Owners linked 2 crashes, 0 fires and 0 injuries to engine & cooling problems on this model year. If you notice symptoms, have the car checked before driving further.
Source: U.S. National Highway Traffic Safety Administration (NHTSA) — owner complaints through October 20, 2026, recalls and defect investigations; fuel economy from the EPA. Complaints are unverified reports and are not proof of a defect. How we rate model years.