Chevrolet Blazer overheating problems

Filed Oct 16, 2026 · Electrical, Steering · FL

Electronically controlled thermostat and sensor fail or get stuck at a much lower coolant temperature causing the dash to display the “steering assist is reduced drive with care.” It isn’t just a message, the steering is much harder to use potentially causing an accident. The ac completely doesn’t work causing potential for sensitive, elderly, or young children and pets to overheat inside, it’s significant risk of injury or death from the hot summer temperatures. The engine coolant temperature gauge is all the way down on C position which isn’t registering how hot/cold the engine gets potentially causing damage to the vehicle and a total loss of the vehicle entirely due to damage from the engine overheating. After doing research online, this problem is affecting all years of the 2019+ blazers with the 3.6L V6 engine AND other known problems with other models and years of their other lineup of cars, it’s very widespread across their platforms. So what are people supposed to do when it isn’t? Pay an $3800+ repair bill to GM when they KNOW it’s more widespread than just this year/make? This is a scam. I’m reporting this complaint to raise awareness and hopefully GM will do the right thing.

Filed Sep 16, 2026 · Engine, Wheels · MI

My 2021 Chevrolet Blazer has experienced repeated problems involving the cooling system and is now exhibiting recurring symptoms that concern me about the vehicle’s reliability and safety. In 2023, the vehicle required a radiator/cooling-system repair. In 2024, it again required radiator/cooling-system repair, which was performed under warranty. The vehicle is now experiencing an abnormal humming/clicking noise from under the hood. The problem initially occurred primarily after rain but has become increasingly frequent. When the noise occurs, the air-conditioning system stops cooling properly and blows warm air. The check-engine light has also illuminated intermittently. The exact component currently malfunctioning is unknown. The vehicle remains available for inspection. Because the symptoms involve the engine compartment and follow multiple previous cooling-system repairs, I am concerned about the possibility of overheating, loss of proper cooling-system operation, an unexpected breakdown while driving, or another mechanical failure that could place the occupants or other motorists at risk. Authorized Chevrolet dealerships previously inspected and repaired the vehicle’s cooling system in 2023 and again in 2024. Despite those repairs, significant symptoms have returned. The current problem has not yet been definitively diagnosed, so I cannot state that the present failure is the same component previously repaired. The warning symptoms include the abnormal under-hood humming/clicking, loss of cold air from the air-conditioning system when the condition occurs, and an intermittent check-engine light. The symptoms have become more frequent over time. I am reporting this because of the recurring nature of the problem and the vehicle’s history of multiple cooling-system repairs. I request that the federal safety agency document and evaluate this complaint together with any similar complaints involving this model and model year.

Filed Sep 3, 2026 · Transmission · MI

Vehicle: 2024 Chevrolet Blazer VIN: [XXX] Component: Engine Cooling System (Radiator) Description of Incident: On XXX the vehicle was brought in for a routine maintenance service at approximately 20,000 miles. During the inspection, technicians at Hamilton Chevrolet in Warren, Michigan discovered a premature radiator leak. The servicing technician noted that this is a common failure on modern Blazers due to a manufacturing material mismatch, specifically where the plastic end tanks meet the aluminum radiator core. This structural component failure poses a severe safety risk. A rapid loss of engine coolant can cause immediate engine overheating, thermal management failure, and a sudden loss of vehicle propulsion while driving at highway speeds, significantly increasing the risk of a crash. Corrective Action: The defect was located and the radiator was subsequently replaced under the factory warranty by Hamilton Chevrolet (Warren, MI). However, this failure occurred far too early in the vehicle's lifecycle, indicating a structural or material defect in the OEM radiator seams. Please investigate this issue, as premature cooling system failures on this model year present an ongoing safety hazard. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Aug 2, 2026 · Engine · PA

The vehicle’s radiator developed a coolant leak that was discovered and confirmed by the dealership during a routine oil change, tire rotation and state inspection. There were no warning lights, warning messages prior to the dealership discovering the leak. The radiator required replacement. The dealership also told me that they had the replacement radiator on hand because this type of radiator failure had been occurring fairly often with this type of vehicle. The radiator failure presented a potential safety concern because a coolant leak can worsen without warning and result in a sudden loss of coolant, engine overheating, or vehicle breakdown while driving. Because there were no warning lamps or other symptoms before the leak was discovered, we may not have had any indication that the cooling system was failing. The problem was confirmed by the dealership during inspection, and the dealership determined that the radiator was leaking and needed to be replaced. The vehicle/component was inspected by the dealership. No manufacturer, police, or insurance inspection has occurred, to my knowledge. There were no warning lamps, messages, overheating, or other noticeable symptoms prior to the dealership finding the leak. The vehicle is only three years old, with 39000 miles on it at the time of the failure. I am reporting this because a radiator failure at such a young vehicle age, particularly one that develops without any warning to the driver, could potentially create a safety hazard if the coolant loss becomes severe while the vehicle is being operated. I’ve seen many complaints in online forums that this is an ongoing issue with these radiators used by Chevy. It seems the replacement radiators are having the same issues. Why can’t something be done? Dealership information: #1 Cochran Chevrolet Cranberry [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Jul 22, 2026 · AZ

The radiator had a crack that nobody located even though I had been smelling antifreeze since I purchased it at 24,000 miles just over a year ago. I brought it in for an oil change today because I was leaving town for the weekend tomorrow and now a hole had blown through the bottom of the radiator. Had this happened when I was in a remote area of the mountains without cell service this could have been a very big problem. Or had it blown while traveling up the mountain pass it would have put my life and others passing me on the road at risk. There weren't any warning lights on and the car never overheated. There weren't any outward leaks up until the hole was blown in the radiator. I have had it in several times for oil changes and there were never any visible leaks noted. Luckily my engine never blew because I've been driving with a cracked radiator for at least a year now.

Filed Jun 14, 2026 · Electrical, Engine · FL

BROUGHT MY CAR TO CHEVROLET CENTER IN WINTER HAVEN FLORIDA BECAUSE I HAD 2 DIAGNOSTIC CODES SHOW UP WITH A CHECK ENGINE LIGHT, THE CODES WERE (U1345: Indicates a communication fault on the LIN (Local Interconnect Network) Bus, usually tied to modules like the active grille shutters, cooling fans, or charge air cooler (CAC) pump.U0632: Indicates lost communication specifically with Cooling Fan 1.) THE DEALERSHIP TOLD ME THEY DIDN'T FIND ANY CODES IN THE SYSTEM AND THEY TRIED TO CHARGE ME $165 FOR A DIAGNOSTIC FEE. RIGHT AFTER I LEFT THE DEALERSHIP I WAS HAVING THE SAME CODES POP UP, WITH THE CHECK ENGINE LIGHT AND MY CAR WAS OVERHEATING. CHEVROLETS ECM/PCM WARRANTY IS 8 YEARS OR 80,000 MILES.

Filed Jun 11, 2026 · Transmission · WA

I am submitting this complaint regarding my 2020 Chevrolet Blazer and what appears to be a widespread cooling system defect. My vehicle has developed a coolant smell outside the vehicle, which raises concerns about a coolant leak from the radiator. After researching the issue, I discovered that numerous Chevrolet Blazer owners have reported similar coolant-related problems, including radiator failures, coolant leaks, and persistent coolant odors. These complaints are widely discussed across online forums, social media, and owner groups. General Motors appears to be aware of this recurring issue, yet many owners continue to experience failures within and outside of warranty coverage. The coolant smell is concerning because it may indicate a leak within the cooling system, which could lead to overheating, engine damage, loss of vehicle reliability, and potential safety risks while driving. Owners should not be experiencing major cooling system failures on relatively modern vehicles. I request that the federal safety agency investigate the cooling system and radiator issues affecting the 2020 Chevrolet Blazer and determine whether a defect exists that warrants a recall or other corrective action. The number of similar complaints suggests this may be a systemic issue rather than isolated incidents. General Motors should be held accountable for addressing this widespread problem and providing a permanent repair solution for affected owners. Thank you for your attention to this matter.

Filed May 25, 2026 · Electrical, Engine · MD

Electronically controlled thermostat and sensor fail or get stuck at a much lower coolant temperature causing the dash to display the “steering assist is reduced drive with care.” It isn’t just a message, the steering is much harder to use potentially causing an accident. The ac completely doesn’t work causing potential for sensitive, elderly, or young children and pets to overheat inside, it’s significant risk of injury or death from the hot summer temperatures. The engine coolant temperature gauge is all the way down on C position which isn’t registering how hot/cold the engine gets potentially causing damage to the vehicle and a total loss of the vehicle entirely due to damage from the engine overheating. GM sent out letters to 2021 blazer owners which included a special coverage number N252508350 applying to people with this year having this problem and they have until 2036 or 150,009 mi to get the repairs made free of charge, they just bring the document with the special repair codes to the dealer and they fix it free of charge. After doing research online, this problem is affecting all years of the 2019+ blazers with the 3.6L V6 engine AND other known problems with other models and years of their other lineup of cars, it’s very widespread across their platforms. So what are people supposed to do when it isn’t the 2021 year? Pay an $800+ repair bill to GM when they KNOW it’s more widespread than just this year/make? This is a scam. I can’t even do the repair myself because I’m having trouble finding the correct parts online and not only that the repair is extensive, the whole top half of the engine needs to be taken apart just to get to the thermostat, we’re talking the airbox and intake manifold, all the plastic parts and shrouds and sensors covering engine, the fuel rail and injectors, pipes and clamps, engine coolant needs drained and refilled. It’s a major fix. I’m reporting this complaint to raise awareness and hopefully GM will do the right thing.

Filed May 23, 2026 · MA

Thermostat fails resulting in steering power reduced, temperature goes to C and fan runs overtime. This thermostat or temp sensor fails intermittently and fixes itself. Car could be overheating and you wouldn't know. This part is recalled on 2021 Blazers already.

Filed May 17, 2026 · Engine · MI

Car is overheating with multiple engine codes. Unable to drive. Car power is reduced and shortly after will start overheating.