Engine And Engine Cooling Problems of Chevrolet Blazer - part 2

Just took my car to the chevy dealership today and had them go over the car because I keep getting the message steering assist has been reduced and the fan is constantly running at the highest speed and it also makes it where I can not use the a/c or heat in the car! I don’t know the code off hand but it has something to do with the cam shaft and the thermostat for the antifreeze! from what chevy told me today it is a $9000 job to tear down the left side of the engine because the camshaft carrier gasket is leaking oil! which is probably why that code is popping up. Or from what I was told today it could be from the battery which I believe they were trying to shift blame. Either way this camshaft stuff really needs to be investigated!!.

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I was driving to work as I normally do and work is only 15 miles away from home I get to work turn into the parking lot stop to scan my badge and I hear knocking noise I thought it was coming from the truck in front of me but after he moved on I still heard the noise and I found a parking spot as soon as I could and the engine light on the dash came on and the motor that was knocking is definitely my Blazer with only 11,222 miles on it. I always keep up on my vehicles maintenance in fact I just had the oil changed at ray skillman gm dealership2/16/26 it had 10,960 miles on it. Before that I had the oil changed at ray skillman 08/20/25 it had 7,720 miles on it then and before that. The very first oil change 22/ may /25 the mileage was 5,354 on it was at hare Chevrolet where I purchased this Blazer rs brand new it had 34 miles I always get the oil changed when it gets to 25%.

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| issues first appeared recorded on 3/9/2026, while odometer read 49,663 miles. Check engine light was caused by error codes p0128 and p01f0. This causes the following issues: * check engine light to appear on the dashboard. * engine temperature gauges to be unreliable at times or completely non functional at others, as it will constantly read the engine temperature "cold". * air conditioning unit to become unreliable at times or completely non functional at others, and only blow hot air. * radiator fan will be stuck running at max speed despite current engine temperature. * a "reduced steering assist" message will periodically appear on the dashboard. * a "service esc" message will periodically appear on the dashboard. * remote start will becomes non functional. | car was taken to a license Chevrolet dealership and had full thermostat housing and thermostat sensors replaced. Dealership confirmed all replaced parts are working correctly and as intended. After picking up the vehicle from the dealership, and driving car for roughly 30 miles, the check engine light appeared on the dashboard again causing all previous issues to return. | several other chevy Blazer 2020 owners have complained of the same issue online, and in forums such [xxx] . | information redacted pursuant to the freedom of information act (foia), 5 u. S. C. 552(b)(6).

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.

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The vehicle experiences a constant cooling system failure that appears to be related to the thermostat. Beginning at approximately 40,000 miles, the engine cooling fan started running continuously at high speed whenever the vehicle is operating. At the same time, the air conditioning stopped functioning properly and the vehicle began displaying a warning message indicating that steering assist is unavailable or reduced. The vehicle is available for inspection upon request. This condition creates a safety concern because the steering assist warning indicates a potential reduction or loss of power steering assistance, which could increase steering effort and make the vehicle more difficult to control, particularly during low-speed maneuvers or emergency situations. The warning appears during normal vehicle operation and can distract the driver. The ongoing failure of multiple vehicle systems raises concerns about the safe and reliable operation of the vehicle. The problem has been present continuously since first appearing at approximately 40,000 miles and is fully reproducible. The condition occurs every time the vehicle is driven and has not corrected itself. Symptoms include the engine cooling fan running continuously, loss of air conditioning, and a steering assist warning message. Based on reports from other Chevrolet Blazer owners experiencing similar thermostat-related failures, this may represent a common defect that warrants investigation and consideration for a safety recall.

2020 chevy Blazer rs 3. 6l having intermittent issues with ‘check engine’ light activating and giving code p0128 - indicating “coolant thermostat (coolant temperature below thermostat regulating temperature)”. Symptoms include: - temp gauge drops to reading “c” (cold), - ac blows warm/hot air, - dash displays message, “steering assist is reduced, drive with care”, - radiator (electric) fans run full speed. It seems that the computer is interpreting the engine coolant temperature sensor drop as a ‘stuck open’ thermostat, thus the indicated code. However, at the same time it also appears to assume a bad coolant temp sensor, and failsafes to disable the ac and set the radiator fans to max to avoid potential overheating. The problem with this is that this can occur after driving for some period that the engine is suitably warm, then I can pull off the road, disconnect the battery for a few minutes, and everything goes back to normal operation. A broken thermostat would not behave this way. * this happened in Mar 2025 - after disconnecting the battery about 5-6 times over about a 1wk period the code cleared and we were able to pass inspection. The issue did not reoccur until about the same time this year. It has been recurring periodically since. * after reading numerous postings on this issue, with numerous different vehicles that have this engine and computer, I have no faith that the dealership will provide a solution other than charging me to replace the thermostat, and ending up with the same problem a few weeks later.

Faulty thermostat. Check engine light comes on due to thermostat getting stuck open and needing to be replaced. This is terrible for the engine and the environment.

On two separate occasions the vehicle lost all power while driving. On December 5, 2025 turning on to a main road from parking lot the vehicle shut off with no prior warning lights. Shifted vehicle to park. No power to anything, unable to unlock doors, unable to turn on hazard flashers, stuck in the middle of the road at night. Waited a minute and pressed the start button and vehicle started with no problem. Again, on February 24 , 2026 making a left turn in intersection, without any warning the vehicle shut off… no power at all. Stuck in middle of road with no lights , no hazard flashers ,unable to get out of the car. Few minutes later vehicle started again. The vehicle did not stall while stopped, it completely lost power while moving. Reported problem to west herr Chevrolet of hamburg NY , brought vehicle in to dealership on February 25, 2026 and they were “unable to duplicate the concerns” the dealership paperwork states that the vehicle stalled while stopped, this vehicle lost all power while it was moving. We now have the vehicle back in our possession but are extremely concerned for our safety and the safety of others.

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The contact owns a 2020 Chevrolet Blazer. The contact stated that while driving at an undisclosed speed, the check engine warning light illuminated. The vehicle was taken to an independent mechanic, where it was diagnosed with vvt sensor failure. The sensors were replaced; however, the failure recurred. The vehicle was taken back to the mechanic, where a solenoid was replaced. The vehicle was repaired. The contact was informed that if the failure recurred, there might be an internal engine failure. The dealer was not contacted. The manufacturer was notified of the failure and referred the contact to the NHTSA hotline to report the failure. The failure mileage was approximately 70,000.

When shutting off the car, the fan continued to run. I started the car up again to see if this would allow the fan to turn off. No luck. The steering assist was dis-enabled on the dash. I took my car to the dealer to find out that it has a bad thermostat and that my radiator was leaking. The thermostat was covered but I had to use my extended warranty to pay the additional repair. My deductible for my extended warranty is $300. 00. My daughter has a 2021 chevy Blazer and the same situation happened. There was a recall and all her parts were covered.

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Thermostat housing replacement + dexcool: p0128, thermostat stuck. Was told this can cause engine to overheat.

The 2021 GMC Blazer (and related chevy Blazer models) is experiencing recurring radiator failures, often requiring multiple replacements within short timeframes. The radiator was replaced in March 2024 and in early 2025 I went for an oil change and complained of smelling coolant and asked if it could be checked and was told nothing was wrong. I was told again in November 2025 that it has a leak and went to have an oil change in February 7, 2026 and was reminded that the coolant was low and the radiator needs replacing when I was first told I did not believe it to be true as it has been replaced before and I asked that it be checked and was told nothing was wrong.

See all problems of the 2021 Chevrolet Blazer 🔎.

On February 4, 2026, my wife drove to the bank, a trip of about 10 to 15 minutes, and turned off the car at the atm. When she tried to leave, the vehicle wouldn't start. After a while, she opened and closed the door and locked and unlocked the car twice with the remote control, and the vehicle started and she was able to drive, but all the warning lights on the dashboard remained on. It is currently at a Chevrolet dealership for diagnosis.

While idling in my driveway, the engine started to shake and the check engine light came on. Got it diagnosed and was told by a private repair center that we had lost compression in cylinder 4 and that it was not worth the repair and we needed to replace the engine. Got it towed to the dealership, bill fox Chevrolet, for a 2nd opinion and they confirmed what the private shop had said. Because the vehicle was well maintained with regular preventative maintenance, it was deemed the failure was not the fault of the owner. Gm extended a goodwill warranty to help cover the cost of the engine replacement (70% coverage. We were 1 month and 2,000 miles past our warranty). They never told us root cause, only that it would have cost more money to repair it than it would be to get a new engine. The Blazer had been running fine up to that point and was my wife's main mode of transportation. The Blazer only had 62,000 miles on it when the failure occured.

Radiator leak from the bottom left corner (driver side). Slow leak over time, no visible damage (per the service department), likely a manufacturing issue. Entire radiator required replacement.

I received a check engine light which I took to bell tire for diagnosis. Here is there diagnosis comments: the p01f0 code on a 2020 chevy Blazer means the engine coolant temperature is below the normal operating range, often due to a stuck-open thermostat (or both thermostats in models with dual units), a faulty engine coolant temperature (ect) sensor, or low coolant, leading to poor fuel economy and potential wear; fixing it usually involves replacing the thermostat(s) or sensor after checking coolant levels and wiring. After that I took the vehicle to gm dealership. Even though this is a know issue with many vehicles from same year, I was told that my VIN is not part of recall and dealership ended up charging me 600+ to fix the issue. I am reaching out to seek help as I had exact same problem but gm is not covering the repairs because my VIN is not in the recall. How is that possible?.

I bought this car brand new. 0 miles. I’ve had an oil leak fixed once in it. And now it’s leaking oil again. I have to have it put back in the shop and pay out of pocket once again for now fault of mine. The first time it was leaking from the cam shaft. This is ridiculous. I will also be filing a complaint with chevy.

The engine started acting weird in traffic going down hill on freeway. Eventually turned off turning into my driveway. No warning or engine light. Towed to dealer and is in for inspection, not sure if they can repair or if they have to replace the engine. When it arrived to dealer the engine light was on with a couple misfires.

Around 55,000 miles, my 2021 Chevrolet Blazer experienced a throttle body failure. The check engine light illuminated and the vehicle entered a reduced power/limp mode condition. Throttle response was significantly limited, and the vehicle could not accelerate normally. While the vehicle remained drivable, it took substantially longer to reach speed, which could pose a safety risk when merging into traffic or crossing intersections. Diagnostic trouble code p2101 (throttle actuator position performance) was present. A Chevrolet dealer confirmed an internal throttle body failure and replaced the throttle body assembly. This component is a critical engine control system, and failure could affect acceleration and vehicle control, posing a potential safety risk. The failure occurred well before expected service life and required a costly repair. The component has been replaced and is available for inspection upon request. I believe this may represent a premature defect and should be investigated for similar failures in other vehicles. ?.

This submission is an additional report related to NHTSA complaint #11714381. At approximately 55,000 miles, my 2021 Chevrolet Blazer experienced a sudden throttle body failure while driving. The vehicle entered reduced engine power/limp mode without warning and acceleration was significantly limited. This created a safety concern while driving in traffic, particularly when merging and crossing intersections. Diagnostic code p2101 (throttle actuator position performance) was present. A Chevrolet dealer confirmed an internal throttle body failure and replaced the throttle body assembly. Although the repair was completed, this failure occurred at relatively low mileage for a critical engine control component. A sudden loss of acceleration can pose a safety risk depending on traffic conditions. Since filing my original complaint, I have identified multiple similar reports online and in owner forums describing premature throttle body failures in gm vehicles with similar symptoms (reduced power/limp mode and limited acceleration). This suggests the possibility of a broader pattern involving this component. I am submitting this additional report so that NHTSA has a complete record of the incident and potential pattern of premature throttle body failures. If this issue is widespread, it may warrant further review or investigation as it affects vehicle acceleration and safe operation.

Engine showing po128 code. Steering assist system reduced power. Engine fan constantly running. Engine temp on dash is stuck on the "c" mark, doesn't move. Thermostat and temp sensor replaced, issue continues. This is a very common problem on gm vehicles with the 3. 6l around the 60,000 mile mark. Gm needs to get it figured out.

For about a week and a half my car had made a high pitched wheezing/hubbing sound when started cold. This occurred at all temperatures cold and warm. Yesterday December 13th I went to run some errands and about a mile into my drive my 2021 3lt 3. 6 v6 Chevrolet Blazer lost the ability to power itself. There was no electrical problem however the power train lost power all gears drive and reverse. I was able to get off the roadway without incident. I scan my check engine light and had several check engine lights including a p 0796.

2020 Blazer, 65,000 miles. Temp stuck on cold, a/c blows warm aor and driving assistance off. The radiator fan runs continuously. Check engine light on.

Thermostat/thermostat sensor and complete water outlet system replacement at only 52,377 miles. The defective part was located under the intake manifold requiring its removal, excessive labor cost for the repair, and potential future engine issues due to exposed/open head gasket for the repair.

My 2021 Chevrolet Blazer experienced a radiator failure at approximately 42,000 miles. The radiator and cooling system malfunctioned, causing coolant loss and triggering a warning light on the instrument panel. The failed radiator is available for inspection upon request. This defect put my safety and the safety of others at risk because a compromised radiator can lead to engine overheating, sudden loss of power, or even steering assist reduction while driving. These conditions increase the likelihood of an accident, particularly at highway speeds. The problem was confirmed by my Chevrolet dealer, who diagnosed the radiator as needing replacement. They initially quoted $1,800, later reducing the cost to $915. 90 after acknowledging that approximately 20 customers per month at their dealership alone are experiencing the same issue. This indicates the defect is widespread, at least regionally, and may be systemic across the model. The vehicle has been inspected by the dealer service department, which is an authorized gm representative. No police or insurance inspection has occurred. Prior to the failure, a warning lamp illuminated on the instrument panel, alerting me to a cooling system issue. This was the first symptom I noticed before bringing the vehicle in for service. I believe this premature radiator failure represents a systemic defect in the 2021 Chevrolet Blazer’s cooling system. It occurred well within the 5?year/60,000?mile warranty period, yet the dealer claimed the radiator is not covered. I am requesting NHTSA investigate this issue, as it appears to affect many owners and poses a significant safety risk.

Car was running fine yesterday, today does not want to start. Thought it was the battery, bought anew battery. Still wouldn't start. Rest of cat is getting great power. Code reader is reading its a fuel pump control moduler which just so happens to be in an open recall for my exact year of vehicle yet my VIN number does not pop up on the GMC website under active recall. I have a 2021 chevy Blazer .

In September 2023, when getting my vehicle serviced for a routine oil change, I was told there was a leak in my radiator. They replaced the entire thing under warranty. On November 15th, 2025, while driving on the highway heading home from out of town with my children, an error flashed up saying “steering assist is reduced – drive with care” upon arriving home, the fan on my car was running on high for a solid 10 minutes after turning the car off. No recall but special coverage n252508350 covers the thermostat replacement. Upon inspection by a mechanic, I was informed that the radiator is also leaking again in the exact same spot as it was previously. It should be noted I have never seen leaking fluid in my garage/driveway. I’ve driven less than 10,000 miles since the radiator was replaced previously. If there is a known problem with the coolant system which can cause overheating and steering assist issues, why isn't the faulty radiator and thermostat recalled. The radiator is cased in plastic to aluminum. Plastic can easily catch fire if a car overheats. The casing also prevents an owner from even knowing if there is a leak since the plastic is catching leaks - the mechanic informed me that's why I didn't know about both times it leaked. This is a 4yr old car with 46k miles, twice replaced radiator and thermostat. A recall should be issued since both problems could potentially cause a fire from an overheated engine & loss of steering assist while driving. A google search quickly showed me thousands of other chevy Blazers from 2019-2021 with reoccurring thermostat and radiator issues. I feel unsafe driving in my vehicle but still owe too much to even trade it in for something else. I've owned dozens of vehicles in my lifetime, used and new and keep them 8-10yrs and have never had to replace a thermostat and radiator. This vehicle is dangerous due to gm/chevy's cheap radiator model and thermostat which could overheat and catch fire.

The radiator developed a leak at around 36k miles and needed to be replaced. My understanding is that this is an ongoing problem with this vehicle.

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We are noticing the coolant meter seems to be stuck on c, the ac is not blowing cold and we are getting a message that action required steering assist is reduced, drive with caution. Today the brakes slammed on by themselves and almost sent my wife thru the windshield. Luckily she was in a clear area with no other cars around.

Car is displaying a “steering assist is reduced drive with caution” engine light is on and fan continues to run for 5-8 minutes after car is turned off. Was told by a mechanic it is a p0128 code, coolant thermostat. This is the third time it has happened in the last year. Other two times the codes cleared.

Radiator failure caused power steering assist to not function properly and insufficient vehicle heat function. Engine electric fan would run continuously after vehicle shutdown.

Put my car into park and the fan kept running continuously. I noticed that the engine temperature gauge did not move off of cool either. When I drove it, I got an alert that the ‘steering assist was reduced’ and shortly after my check engine light came on. My safety was at risk due to the fact that I couldn’t monitor my engines temperature and it very well could have been overheating and I would’ve never known. I took it to the dealer and they did confirm that my thermostat was stuck open and wasnt allowing my engine to get up to temperature. My ecm module had to be replaced as well. The mechanic said, had it closed my engine would’ve overheated with no signs until it was too late.

Engine temperature gauge is not working. Dash is displaying driver assist issue and steering intermittently locks up while moving. Air conditioning does not work and cooling fan is running at high speed. Thermostat and coolant temperature sensor need to be replaced. Such a high number of these vehicles are failing that I can’t even get factory parts.

"steering assist reduced” warning message appears on dashboard display and temperature gauge stuck on cold on the dashboard display. I understand this such a common issue with the 2019 and 2020 Blazer that general motors has issued technical service bulletins but refuses to repair these vehicles for free. This is unacceptable! issue a mandatory recall therefore gm must perform the repairs for free.

The thermostat failed on a trip locking in 0 temperature reading and steering assist warning. Licensed mechanic repaired on 10/9/25 invoice is available. 67,509 miles. This could risk overheating and destroying the engine and might cause accident. Two other friends have had similar issues, appears to be a safety defect!.