Engine And Engine Cooling Problems of GMC Acadia - part 1

I am submitting this complaint regarding ongoing mechanical and electrical issues with my 2021 GMC Acadia that have been occurring intermittently for approximately the past year and a half. The primary issues involve the coolant temperature sensor, thermostat system, engine cooling fan, and dashboard warning messages. The vehicle repeatedly experiences problems related to the coolant temperature sensor and thermostat. During these episodes, the engine cooling fan continues running even after the vehicle has been turned off, sometimes for an extended period of time. In addition, the dashboard frequently displays the warning message: “steering assist is reduced – drive with care. ” these warning messages and symptoms occur off and on without consistent resolution. The vehicle has already undergone repairs, including replacement of the radiator, yet the problems continue to return. Despite previous service attempts, the underlying issue has not been permanently corrected. The recurring nature of these problems raises concerns about the reliability, safety, and dependability of the vehicle, especially considering the steering assist warning and possible overheating or electrical system concerns connected to the cooling system malfunction. The repeated failures have caused significant inconvenience, concern for safe operation of the vehicle, loss of confidence in the vehicle’s reliability, and ongoing disruption due to repeated repair needs. I am requesting a thorough diagnosis and permanent repair of the coolant temperature sensor, thermostat, cooling fan system, and any related electrical or control module issues contributing to these recurring problems.

See all problems of the 2021 GMC Acadia 🔎.

Bought the Acadia in June of 2021, in December of 2022 had to have the radiator replaced due to it leaking. This was found on routine maintenance and was not having any issues whatsoever. I received no alerts on my dash such as a check engine light. Fast forward to March 2026, I received a message of "steering assist reduced. Drive with care. " the engine seemed like it was still running despite the car being off. This was happening intermittently and definitely not every time I drove. I made an appointment for the regular oil change and to have this message investigated. Initially they told me it was the temperature regulator, however, they put a new regulator on and tried to re-pressurize the system. The system failed to re-pressurize due to the radiator leaking again. Of course, there was a 2 year warranty on the radiator after it was replaced initially and now we are about a 1. 5 years outside the warranty.

Coolant temperature sensor failed - it is still in the engine. The fan stays on high all the time. And the ac does not want to turn on. The car is extremely hot to drive in during the summer months. I have to transport persons who are seniors and in their mid 80s. It is not safe to drive this car in the summer. I can't tell if its over heating or what is happening. The coolant temperature gauge does not work. The dealer said my car is out of warranty and that the ac will not start until the sensor is replaced. I said that it has less than 50,000 miles. They will not help me. The vehicle has not been inspected anyone other than the service mechanic. The engine light start coming on about a month ago. I drove first to an autoparts store to see if they could help. This is the first time I learned that it could be a bad sensor.

See all problems of the 2020 GMC Acadia 🔎.

The contact owns a 2020 GMC Acadia. The contact stated that while driving the vehicle, it stalled after initially adding fuel. Even though the reading indicated there was 1/8 of a tank of fuel. The fuel gauge failed to move. The thermostat was stuck open. The electric steering was not working properly. The engine light was illuminated. The traction control was turned off. The contact stated that the failure was related to NHTSA campaign number: 20v639000 (fuel system, gasoline). The contact stated that he was a master mechanic. The contact called the local dealer, but the vehicle was not diagnosed or repaired. The contact called two other local dealers, tadd jenkins chevy 409 farnsworth way, rigby, id 83442, and smith Chevrolet. Address: 3477 pioneer dr suite 200, idaho falls, id 83402. The manufacturer was contacted, but no assistance was provided. The failure mileage was approximately 61,699.

The warning steering assist reduced, drive with caution appears. Shift to park appears. Temperature gauge drops to zero. Fan runs on high. A/c & heater don’t not work when this happens. We certainly do not feel safe driving our Acadia like this. Can’t trust that it won’t start on fire.

See all problems of the 2019 GMC Acadia 🔎.

Engine randomly shuts off when driving for no reason. Will restart and check engine light comes on. Has now happened three times , twice to me in traffic. One of those the car went into a limp mode where it wouldn't drive above 30mph at most. This is very unsafe in the middle of highway traffic. The second happened approaching a traffic light , I put the car into neutral and luckily it restarted and check engine light came on. The third time my wife had her friends in the car and it shut off at a light , she had no idea what to do. I had her stay there and brought her our other car. I have read this is caused by a known fuse box issue. They should be made to fix this problem before someone gets seriously hurt driving in traffic.

See all problems of the 2014 GMC Acadia 🔎.

Vehicle would not run due to a failed fuel pump control module. With a non-running engine, the transmission could not be placed into neutral to be able to movie vehicle out of the road. Needed tow truck to move vehicle. This condition placed many people at risk as the vehicle could not be moved out of the way until a tow truck arrived.

See all problems of the 2023 GMC Acadia 🔎.

The vehicle has a serious transmission/drivetrain defect that repeatedly occurs when accelerating from a complete stop, especially onto an incline. The vehicle sometimes does not respond at all when the accelerator is pressed and fails to move, even though acceleration is being requested. In one recent incident, it remained stopped for about one minute before finally responding. During these events, the vehicle jerks and shakes severely and fails to gain speed as expected. This creates a major safety risk at stop signs, intersections, and uphill starts because the vehicle may not move when needed and cannot keep up with traffic. The problem has worsened, and during one of these incidents the check engine light came on. I have video evidence showing the loss of response to accelerator input, severe jerking/shaking, and the check engine light illuminating during the same event. The issue has been reported to dealers and gm customer service but has not been properly resolved.

See all problems of the 2025 GMC Acadia 🔎.

I purchased this vehicle in June 2024 as a demo vehicle with approximately 7,000 miles on it. Within one month of ownership, the vehicle began experiencing serious problems that have continued to worsen. The vehicle currently has approximately 34,000 miles, and the issues have been ongoing from the time of purchase through the present. Since purchasing the vehicle, it has been in the dealership multiple times for the same recurring problems, including but not limited * powertrain issues and loss of power * reduced acceleration while driving * complete electrical failure while driving * engine and electrical warning lights repeatedly turning on * vehicle running excessively hot * water pump replacement * replacement of sensors * thermostat replacement * ongoing engine and electrical system malfunctions despite these repairs, the same problems continue to reoccur. Each time I return the vehicle for service, I am informed that it is a “different issue,” even though the symptoms remain unchanged. This strongly indicates a defective powertrain and/or electrical system that has not been properly repaired. The most serious concern occurred while I was driving on public streets, when the vehicle lost acceleration, electrical power shut off, and the vehicle completely shut down, nearly causing me to be hit by other vehicles. This incident created an extreme safety hazard for myself, my passengers, and other motorists. I have made several formal complaints directly with GMC, and more than four case numbers have already been created regarding this vehicle. Despite these complaints and repeated repair attempts, the problems persist. Given the repeated failures, numerous repair attempts, documented safety risks, and the fact that these issues began shortly after purchase, I believe this vehicle qualifies for relief under applicable lemon laws and consumer protection laws. Incident (critical)vehicle lost acceleration and electrical power and completely stalled while roads.

See all problems of the 2024 GMC Acadia 🔎.

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.

Loss of steering assist code p0128 due to stuck thermostat.

Car has had multiple issues with check engine light coming on for the last 2 years and stays on especially during the winter months. The purge pump has failed multiple times. The cooling fan has run after engine shutting off for multiple years now. The thermostat has been failing for the last 6 months. Now yesterday low power protection suddenly turned on driving on the expressway limiting power in the middle of traffic. Was able to get off at exit without accident and get car home. I guess we have to pay out of pocket to get fixed. This is a known issue that gm fails to include every VIN with the 2021 year or certain models and vins.

We purchased our 2024 Acadia in June 2025. Since we have had the vehicle, it has been in the shop going on 6 times. First the sunroof seal came off, then the antenna cover fell off, the driver side rear panel had to be replaced because it was coming off. Once all this was done then the vehicle started leaking transmission fluid, took it to the dealer to get fixed, once we get it back the coolant starts leaking from the radiator hose, took it in to get repaired, now there is knocking noise coming from the engine/hood. Every time we take it in to get repaired a new problem pops up. We purchased the vehicle to have a safe way to get our kids around and it has been nothing but a headache and run around from the dealership. GMC really needs to resolve this issue. Parts seem to be on never-ending backorder with no eta.

Check engine light codes: p01f0; p0128 engine coolant thermostat opening at a lower temperature than intended. Replace thermostat.

Owner of a 2019 GMC Acadia denali (VIN: [xxx] , current odometer ~87,164 miles), purchased new. In early February 2026, the check engine light came on. Independent diagnostic scan confirmed persistent p0420 code (“catalyst system efficiency below threshold bank 1”) as current, history, pending, and permanent. Inspection showed the front exhaust pipe bracket had snapped, damaging the flex pipe and causing an exhaust leak. This failure mode directly triggers the p0420 code and requires replacement of the bracket and affected flex pipe section. This is a known recurring issue on gm’s lambda-platform vehicles (shared platform, 3. 6l v6 engine, and exhaust system design). Gm special coverage adjustment n212356540 covers 2019 Chevrolet traverse and Buick enclave models for front exhaust pipe bracket separation (resulting in pipe damage, holes, leaks, rattling, or efficiency codes), providing free repair for 15 years or 150,000 miles from in-service date, regardless of ownership. The failure on this Acadia is mechanically identical, yet the model is excluded from coverage despite matching part design and numerous similar owner complaints documented on NHTSA and bbb reports. Multiple attempts were made to resolve through the selling dealership (no response to service inquiries). Matter was escalated to gm executive resolution. Gm required a redundant diagnostic scan at an authorized dealer (additional cost incurred), despite independent confirmation of the issue. Gm ultimately denied any coverage, TSB applicability, goodwill assistance, or further support. The snapped bracket and resulting exhaust leak can produce noise, fumes in cabin, potential component damage, and emissions noncompliance via false/legitimate catalyst efficiency codes. Inconsistent application of coverage for the identical defect across equivalent lambda-platform models raises concerns about a widespread safety/emissions issue affecting 2019 GMC Acadia. Information redacted pursuant to the freedom of information act (foia), 5 u. S. C. 552(b)(6).

Car was taken in for an oil change at 62k miles. Dealer advised that it needed a radiator replaced. At 64k miles it was brought into the dealer for warranty work due to a failing thermostat. While being diagnosed, we were told not only the radiator needed to be replaced, but the oil cooler also needed to be replaced. So a 5 year old car with just over 60k miles had the thermostat/sensor fail and need to be replaced. A radiator fail and need to be replaced and and an oil cooler fail and need to be replaced. Vehicle has been at a gm dealer for all maintenance. No crashes or reasons these parts should fail. Vehicle has never towed anything to but any sort of strain on the cooling system.

The car would not shift causing me to pull over on the side of a highway to restart the car this happened 5 times in a row b4 the car would shift into proper gear.

See all problems of the 2008 GMC Acadia 🔎.

Unknown after diagnosis at the GMC dealership they stated that it is same issue as released in the following: special coverage adjustments: n212356540 front exhaust pipe n222385510 special coverage front exhaust pipe however they currently do not cover our GMC Acadia model year 2022.

See all problems of the 2022 GMC Acadia 🔎.

Thermostat issue (steering assist is reduced drive with care) have changed this sensor 3 times in the past 3 years, there is no excuse for that. The emergency braking almost cause me and my daughter to be hit by a train when my car emergency braked while going over train tracks. This is unexcusable.

See all problems of the 2017 GMC Acadia 🔎.

The vehicle experiences a transmission/drivetrain defect involving delayed gear engagement, hesitation, and apparent slipping. When accelerating from a complete stop (especially onto an incline) the engine rpm increases but the vehicle fails to accelerate as expected. The vehicle jerks and shakes violently and is unable to gain speed. This issue is intermittent but highly repeatable and occurs almost every time when there is a slope immediately after a stop sign. It results in loss of acceleration, violent shaking, and inability to maintain or build speed, creating a serious safety risk in traffic. It first happened around 1 year (early 2026) after the new car purchase (Nov 2025). There are no warning lights or messages. The dealer claimed they were unable to reproduce the issue during a brief test drive without me present and incorrectly attributed it to a bulletin without performing a detailed diagnosis or repair or looking at the video we recorded on the issue. The issue persists and affects safe operation of the vehicle. No inspection has been done by police or insurance. In one instance, this occurred while other vehicles were approaching from behind, creating a dangerous situation where I could not accelerate to match traffic flow. This resulted in a high risk of being rear-ended due to the unexpected loss of acceleration. I am aware of other consumer reports describing similar transmission-related symptoms such as slipping, hard shifting, and hesitation in this model. Some complaints describe transmission issues occurring at low mileage without warning lights.

The engine is spewing oil from the sides of the engine. This is causing overheating and check engine light to come on. Mechanics cannot get an error read on it. There is no oil leak coming from under the engine.

Failed component was thermostat and I do not have possession of it. Over several months, I would receive infrequent and unrepeatable messages of "steering assist reduced" and my temp gauge would drop all the way to the cold side. No other recorded codes were being set after frequent trips to autozone for verification and there were no check engine light warnings. No other signs of vehicle malfunctioning were present either. Recently, a code was finally set p01f0, so I had something tangible to take into shop as the prior condition was not repeatable. Hoping it was only the coolant temperature sensor, then ultimately learned the thermostat had failed - the much more expensive repair option. Seeing this complaint relatively frequently with the 3. 6l engine on NHTSA. Plus, the tech says he has changed at least 100 of these - Acadias, traverses, enclaves, etc. , any gm product with this engine and poor design/position for the thermostat.

Rear heater line leak detected during evaluation of engine code p01f0 and empty expansion tank was noted. There was never any puddle in my garage prior to the incident, and nothing detected after the fact either. Pictures included demonstrate a leak at the double-crimp near the farthest rear point of the vehicle. The other hose behind the drip photo was also leaking at the crimp under the secondary piece of hose insulation. The design of the system requires replacement of the entire heater line assembly (4 pipes, associated hoses and fittings) traversing the entire length of the vehicle. I was told this is a dealer-only part.

Vehicle experiences multiple simultaneous failures including “steering assist reduced / drive with care” warning, extremely loud cooling fan operation, temperature gauge not functioning, tire pressure monitoring system failure, and widespread electrical issues (windows, mirrors, infotainment delay). Issues occurred together and are consistent with numerous owner reports for 2019 GMC Acadia models. Condition affects steering assist and engine temperature monitoring, creating a potential safety risk.

2019 GMC Acadia message: action required steering assist is reduced drive with care both power steering and ac affected, check engine light on, engine temperature gauge off.

The car has over the last few years not turn off due to shift to park. This is concerning, due to we cannot turn the car off unless we strike the shifter few times assuming this is the remedy. It doesn't look like there is any type of recall but there should be.

My car will not park. I get a shift to park error message. I tried restarting and shutting it off. Didn't work. I ended up putting it in neutral turning on the emergency brake and then shutting the car off. I have had no problems with this car to this point, I am a single car owner and my car must be reliable. I can't spend a half hour trying to get the car to shut off.

Unknown. Brakes still squeaking after getting them changed with the bulletin notice. Engine surges and idles rough- dealership could not diagnose. Not accelerating randomly, pedal goes in and it does not engage. Gas tank not filling up all the way. Rear cross tracking warning turned off when it is not turned off. Ac smells rotten and musty.

In the process of taking my daughter to the emergency room I receive a dash notification on my recently purchased 2024 GMC Acadia "car overheating, possible engine failure". My gauges were within normal range and being that I was in an emergency I kept traveling. Leave hospital to head home the error message is gone. The following Monday, January 5th, heading in to work I receive the same error message on my dash "car overheating, possible engine failure". Drove to the nearest mechanic, left my car, and they discover a leak in the upper radiator hose. They call with bad news that the part is on nationwide back order. Gm admitted to a faulty design, in the process of redesign. A spac case with a local gm dealership was opened. Gm would expedite my case if I towed to a gm dealer. I would have to pay for the tow. And just how can my case be expedited if the part isn't available? it can't. I was told the redesigned hose is going on the new models currently being built. I have lost all faith in gm. Today is February 19th and my car is still at the mechanic with no eta on part delivery. I called every gm dealership parts department within 100 miles and get the same response, "we have two hoses with four cars needing it, we have 4 hoses with 8 cars needing it, the hose is hell to find, etc. ". Why has gm not issued a recall on the upper radiator hose. If you have a 2024 GMC Acadia, you will incur this same issue.

Apparently many vehicles like mine and including mine have defective radiator hoses or a poor set up with routing causing issues with the hoses. They are developing cracks/leaks causing poor circulation in the cooling system as well as possible engine failure. In speaking to mechanics and reading forum posts, it is evident that this is a large scale issue.

After I put my car in park my daughter and I were still in the vehicle for a few minutes getting our things with the engine still running. I got out to get something from the back seat, my daughter got out the passenger door and made it to the driver side as I was closing the back passenger door. I was about to get back on the car to get the rest of my things and turn the ignition off but before I could my car was rolling backwards out of the driveway into the street. I was able to jump in the vehicle and put my foot on the brake and the put the gear into park. There’s no way possible I didn’t put it in park with me getting out already and my daughter couldn’t have accidentally shift the gear because she couldn’t have been able to get out, close the door and make it to the driver side before it started rolling away. Once I got the car stopped, I noticed the driver seat was now all the way to the steering wheel and completely to the floor with the headrest also tilting inwards and now the electrical for the seat will not work. There is a recall for this issue but my VIN# is not included. I cannot even drive my car now because the seat is so far up and inclined. What if the seat moves up more while I’m driving and it has me pinned between the steering wheel and the seat. I don’t feel safe driving it, having my daughter as a passenger and it’s really not safe to be on the road. I’m still paying on this car and now I won’t even be able to drive to work. So I’ll probably lose my job. This car has multiple issues and I think is an electrical problem. It’s also a known major defect on this model but still not a recall for my VIN #! none of my interior sound works. Speakers, blinkers, alerts, back up camera. The auto start won’t start, I have to press the key fob multiple times to lock and unlock. This car is extremely unsafe to drive and I strongly feel my cars VIN# should be listed under the recall. Its going to really affect my daily life and means of income. Lemon!.

Purchased the vehicle in good faith, unaware that the check engine light was illuminated at the time of purchase and not informed that this indicated a serious mechanical or emissions-related issue. After purchase, the dealership repaired an emissions-related problem, and the check engine light was no longer present when the vehicle was returned to me. However, within three days of having the vehicle back in my possession, I began experiencing additional issues, including electrical malfunctions and abnormal noises coming from the front wheels. These problems caused the vehicle to feel unsafe to operate and raised serious concerns about its reliability and overall safety. Due to these concerns, I returned the vehicle to the dealership immediately.

Multiple times an alert has been given for "driver assist temporarily reduced, drive cautiously". Additionally, the check engine light has come on, with codes for the cooling system. Cooling system fan (hvac blower) remains on after shutting off vehicle for anywhere from 5-15 minutes. Coolant levels have been checked and are correct. Heat & ac function, however the thermostat gauge on the instrument panel does not read any temperature at all. At this time, the vehicle has not been taken to the dealership for assessment due to financial constraints.

For the 3rd time of ownership the cooling fan stays on after vehicle is turned off and the display “steering assist is reduced, drive with caution”.

The “steering assist reduced” message came on and, when shut off, the fan blows very hard and loud.