Engine And Engine Cooling Problems of GMC Acadia - part 1

See attached file.

See all problems of the 2019 GMC Acadia 🔎.

I was at a red light, I went to drive as the light turned green and my car stopped and wouldn’t drive, I could go into neutral to get out of way but anything the car would stop. There is no codes or lights turned on my dash though.

“steering assist is reduced” warning, p0128 code, thermostat-related symptoms, increased steering effort or other safety concerns while driving. This issue required increased steering effort and affected my wife's driving ability to respond to changing traffic conditions. This is most likely a faulty thermostat housing assembly. This has been well documented temperature gauge problems, cooling system issues, and related warning messages. Our GMC Acadia is a 2022 at4 with 53,500 miles. Gm recently issued special coverage n252508350 for 2021 Acadias with the 3. 6l lgx engine affected by thermostat housing issues. Owners of other model years reporting substantially similar symptoms remain responsible for the repair cost. Please investigate this.

See all problems of the 2022 GMC Acadia 🔎.

The contact owns a 2019 GMC Acadia. The contact stated that while driving at an undisclosed speed, the transmission failed to properly shift gears and the vehicle failed to exceed 40 mph while driving. The contact stated that the transmission failed to shift above third gear. The check engine warning light was illuminated. The vehicle was taken to an independent mechanic, who discovered that there was no transmission fluid inside the torque converter. The vehicle was scanned and displayed an issue with the transmission control module. The local dealer was contacted and confirmed that the VIN was not included in NHTSA campaign number: 20v668000 (power train). The vehicle was not diagnosed or repaired. The manufacturer was contacted and referred the contact to the NHTSA hotline to report the failure. The approximate failure mileage was 154,429.

My Acadia went into limp mode displaying low power mode on the screen and wouldn’t start for a couple days after. Lights started illuminating on the dash as abs, traction control, and stanilitrack, then check engine light came on and my GMC app displayed code p2138. I have had since low power and extremely high gas consumption.

See all problems of the 2017 GMC Acadia 🔎.

Thermostat and cooling sensor went out on my car. GMC issued a special coverage bulletin for 2021 Acadia since it's a widespread issue but not the 2020 (mine) which is also a widespread issue looking online. The repair is over $1000 and should be covered!.

See all problems of the 2020 GMC Acadia 🔎.

The contact owns a 2014 GMC Acadia. The contact stated that while in park(p), the vehicle rolled, requiring the driver to turn off and restart the vehicle, and the vehicle successfully shifted in park(p). Additionally, the contact stated that while driving at various speeds, the vehicle jerked. The contact stated that while driving 60-65 mph, the vehicle shut off, and the steering wheel and the wheels locked up. The contact was barely able to pull over to the side of the road, where the contact waited before restarting the vehicle. The contact stated that the check engine warning light was recently illuminated. The vehicle was towed to two independent mechanics, where several diagnostic trouble codes associated with the transmission and the transmission module and solenoid were retrieved. The contact was then referred to a transmission specialist, where the vehicle was towed and was being diagnosed. The vehicle was not repaired. The manufacturer was not contacted. The failure mileage was approximately 160,000.

See all problems of the 2014 GMC Acadia 🔎.

The contact owns a 2010 GMC Acadia. The contact stated that while driving at an undisclosed speed, there was an abnormal sound coming from the vehicle. The contact became aware of white smoke coming from the vents. No warning lights were illuminated. The vehicle was driven to the shoulder of the road. The contact and minor children exited the vehicle. The contact stated that while exiting the vehicle, there was fire coming from underneath the hood. The fire truck arrived on the scene and extinguished the fire. The vehicle was towed to a local tow yard. The vehicle had liability coverage, and the insurance company declined to inspect the vehicle. The contact stated that the vehicle was a total loss. The failure had occurred while the contact's minor children were seated in the rear seat of the vehicle. The contact and the children sustained smoke-related injuries. The contact and the children later received medical treatment for the smoke-related injuries. The manufacturer was made aware of the failure, and a case was filed. The manufacturer declined to inspect the vehicle. The failure mileage was approximately 163,000.

See all problems of the 2010 GMC Acadia 🔎.

Blind spot monitor goes off for everything. Engine has chirping noise. Brand new.

Hesitants and shudders when shifting into 2nd gear.

See all problems of the 2018 GMC Acadia 🔎.

The contact owns a 2012 GMC Acadia. The contact stated that the vehicle failed to release from low gear while at a stop. The transmission was backed up. The engine light was illuminated. The local dealer was not contacted. The vehicle was not diagnosed or repaired. The manufacturer was contacted, who confirmed there were no recalls. The failure mileage was approximately 213,766.

See all problems of the 2012 GMC Acadia 🔎.

Steering assist is reduced brake assist reduced seems to be a defective thermostat and sensor . Temp gauge is below normal operating temperature this needs to be addressed by gm should be a recall as this can be a costly repair. Many reports of same issue.

The contact owns a 2019 GMC Acadia. The contact stated that while driving at an undisclosed speed, a “steering assist is reduced ” warning message unexpectedly displayed. The contact also stated that the thermostat became inoperable. Additionally, the thermostat information was no longer displayed on the instrument panel. The vehicle was taken to the dealer, where it was diagnosed that the thermostat had failed and needed to be replaced. The vehicle was not repaired. The manufacturer was made aware of the failure and referred the contact to the NHTSA hotline for further assistance. The failure mileage was approximately 48,500.

Shortly after purchasing my 2019 GMC Acadia with approximately 52,000 miles, the vehicle displayed a "steering assist is reduced. Drive with care. " warning message and illuminated the check engine light with diagnostic code p0128 00 (engine coolant temperature below thermostat regulating temperature). I disconnected and reconnected the battery, after which both the warning message and check engine light disappeared. However, the engine coolant temperature gauge then began behaving erratically. On multiple cold starts, the gauge would immediately indicate that the engine was already at normal operating temperature even though the engine had been sitting long enough to be completely cold. This led to a diagnosis of a thermostat and/or engine coolant temperature sensor failure. After researching the issue, I found many other owners reporting the same thermostat and engine coolant temperature sensor failures. I believe this is a widespread defect that should be investigated because incorrect coolant temperature readings can prevent the driver from knowing the true engine temperature and may result in improper engine temperature regulation, overheating, and possible engine damage.

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.

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.

[symptom & safety hazard] while driving my 2020 GMC Acadia 3. 6l v6, the driver information center displayed the warning: "steering assist reduced, drive with care" (sardwc). Steering effort increased abruptly, the engine temperature gauge dropped to cold/zero, and the hvac system lost air-conditioning function. The warning and reduction in steering assist presented a safety hazard and increased the risk of a crash. [diagnostic findings] vehicle diagnostics identified dtc p0128 - engine coolant temperature below thermostat regulating temperature. A GMC certified dealer technician diagnosed a failed engine coolant thermostat housing assembly. [manufacturer information] gm documentation links dtc p0128 and invalid engine coolant temperature signals to the "sardwc" condition. Gm bulletin 17-na-158 states the “sardwc” condition is caused by an invalid coolant temperature signal and the steering module relies on coolant temperature information for steering-assist compensation. Gm bulletin pit5967 directs technicians to diagnose and repair dtc p0128 when the warning message is present. In oct 2025, gm issued n252508350 for 2021 Acadia vehicles equipped with the 3. 6l lgx engine due to an engine coolant thermostat condition. My 2020 Acadia is part of the same generation vehicle platform and is equipped with the same 3. 6l lgx engine. It experienced the same thermostat-related failure symptoms, including dtc p0128 and the "sardwc” warning. [reason for complaint] I am filing this complaint because a thermostat-related cooling-system failure resulted in a steering-assist warning and reduction in steering assist while the vehicle was being driven. Moreover, gm issued n252508350 for 2021 Acadia vehicles equipped with the 3. 6l lgx engine due to the same engine coolant thermostat condition, yet similarly affected 2020 Acadia vehicles are not included. Nhtsa should investigate whether additional 2020 vehicles are experiencing the same failure sequence and resulting safety risk.

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.

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 🔎.

Thermostat issue causing check engine light as well as steering assist to be turned off. Fan constantly runs. Reset code and immediately is fine again for anywhere from a day to weeks but then happens again. Car is just out of warranty but seems to be common occurrence as there is a service bulletin for the 2021 model.

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 🔎.

I am getting the known p0128 code. My engine says it's cold when it's not, my ac isn't working, and I am getting a message that says "steer assist reduced. Drive with care". This is a known problem and complaint of the GMC Acadia.

Display suddenly says "steering assistance reduced, drive with care" temp gauge goes to c and stays there. Radiator fans speed up and stay on after the car has been turned off. Dealer unable to find a diagnostic code for the problem.

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 🔎.