2020 GMC Acadia

Engine coolant thermostat failed under 55,000 miles and had to have it repaired on my 2020 Acadia. The 2021 Acadia has a recall on the thermostat.

1. Shift to Park failure, P0700/P187e internal sensor, causing me to have to get a rebuilt transmission. 10/2025 2. Transmission shudder/hard-shifting ongoing 2022-2025 3. Coolant/thermostat issues. Steering Assist Reduced" message, fans stay on HIGH, no AC, engine temp on ZERO ongoing since 2024 3. Start/Stop button failure multiple times (replaced 3 times) 4. Rack and pinion/steering gear (would not return/ got stuck while turning) got new rack and pinion 2023 5. Water pump leaking, replaced 4/2024 6. Since 2023, have had ongoing “Timing OVER ADVANCED”, warning issues since 2023. This is TOO MUCH for a New car!!! I’ve owned MANY cars and NEVER had this many issues!!! There appears to be multiple design flaws with this model and similar models!

Steering Assist reduced drive with care message. This is an extremely common issue and should be a recall. ALOT of people including my dealer service advisor has this issue with their vehicle this message comes up fans kick on high a/c stops working and temp gauge stops working. It can be reset by unplugging battery or clearing the code.

The contact owns a 2020 GMC Acadia. While the vehicle was at the dealer for maintenance, the contact was informed that the radiator was leaking and needed to be replaced. In addition, the contact was advised that there was coolant intrusion. The contact stated that it was not specified if the coolant intrusion had gone into the engine. No warning lights were illuminated. The vehicle was not repaired due to the cost. The contact was informed that the fueling system needed cleaning service, as well as the brake fluid and transmission fluid needed to be serviced. The vehicle was taken to several independent mechanics, and no leaks were found with the radiator. The manufacturer was not made aware of the failure. The failure mileage was approximately 62,000. The VIN was not available.

I own a 2020 GMC Acadia that has experienced multiple major mechanical failures within one year. In January 2025, at around 74,000 miles, the transmission failed completely with no warning or clear indication of what was wrong. The vehicle suddenly lost power while driving, creating a safety risk for me and my child. I was quoted around $12,000 for the transmission replacement initially before getting GM involved. GM covered all but approximately $3,600 out of pocket for me and also covered 100% of the timing cover replacement, which was found to be defective during the same repair. Now, at about 84,000 miles, the thermostat has failed, triggering the check engine light. This repair has not yet been completed and is estimated at around $1,500. My dealership informed me they keep thermostat parts in stock because this failure is so common on Acadias. There were no warning lamps or symptoms before any of these failures occurred. All repairs and diagnostics—including the current issue—were done at the same GMC dealership where I’ve always had my vehicle serviced on time. I’ve been a loyal customer and maintain my vehicle according to the recommended schedule. Despite that, I have faced repeated high-cost repairs on a 5-year-old vehicle with relatively low mileage, which has been financially and emotionally overwhelming—especially as a parent who recently lost employment. Having the transmission, timing cover, and now thermostat all fail in such a short time clearly raises concerns about the reliability, safety, and manufacturing quality of the 2020 GMC Acadia’s powertrain and engine systems. Given that GM has already covered most of the transmission and timing cover repairs and dealerships acknowledge frequent thermostat failures, this appears to be a systemic defect that warrants formal investigation.

Vehicle will shutter or buck at variable speeds like, 35-38 mph, 40-45 mph and so on. if I take my foot of the gas and reapply it will shutter buck again at almost any speed. I took it to a mechanic and there are no codes, no check engine light. Shop recommended changing the transmission fluid so we did. Car still responds the same way, shutters and bucks when reapplying fuel pedal or slow acceleration.

My 2020 GMC Acadia has experienced significant transmission issues, including [slipping / shuddering / “Service Transmission” warnings / loss of drive]. The problem has been diagnosed as a torque converter/transmission failure. GM has acknowledged known defects and issued recalls for 2019–2020 Acadia transmissions related to missing bolts in the start-stop accumulator endcap, which can cause fluid leaks and lead to torque converter/transmission failure. Many other owners have reported similar transmission issues, suggesting a systemic defect with the 9-speed transmission used in these vehicles. Despite these known issues, GM has declined to provide assistance with repairs. This failure compromises the safe operation of the vehicle, and I believe it warrants further investigation and potential recall.