Engine And Engine Cooling Problems of Chevrolet Blazer - part 2

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.

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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.

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

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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.

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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!.

Engine light on, power steering assist, air conditioning stop working diagnostic tool read p0128 coolant thermostat.

Dashboard goes on like a christmas tree (almost all lights turn on abs gas light traction control parking service light) check engine stays on then disappears after a few days. Transmission won’t gear into shifts only stays in one shift.

Was informed at today's oil change that my radiator is leaking and it's something that they are seeing a bunch.

Action required "steering assist warning" drive with caution, temp gage reads cold, a/c stops working, engine cooling fan runs on high speed (even after the engine is shut off), pending p2018 code, with no check engine light (cel). Replaced engine coolant temperature (ect) sensor, problem did not go away. Several reviews suggest to replace the thermostat, check fuses for proper insertion, reroute ect wiring, and possibly replace radiator. Most of these repairs can be very expensive. Chevy Blazer forum states that the issue is a out of range detection of ect sensor reading. Gm needs to determine a true solution and stop guessing at owner expense/frustration.

Check engine light on, message saying "steering assist reduced drive with care", engine temperature gauge not moving from c, and ac not working. I have taken it in to be fixed 3x, and they have fixed it 2/3 times but the message has come back again. It is a big issue in 2019/2020 Blazers according to my research.

Thermostat not working. Causing fan to run as if the vehicle is overheating.

Transmission & engine failure. Press the gas and it doesn’t move the car-feels as if it is trying to change gears and it isn’t working. Car under warranty & still not working. Been to the dealership multiple times and they are unable to fix the issue. No warning signs.

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Thermostat has gone bad. Talked to chevy and they said it is a known issue.

My vehicle lost complete power while I was sitting at red light. The dashboard went completely out and pop back on stating to put the vehicle in park and push the brake to start. After following those instructions the vehicle failed to start and I left disability until onstar notified mpd to assist. While waiting for assistance I was almost hit 3 times. When mpd arrived on the scene they were able to push the vehicle out of traffic. After my vehicle arrived at the shop I was told the power failure was caused by the malfunction of the DC/DC converter output voltage. I see a bulletin was put out but a recall was my made available. I feel this is a major issue due to the vehicle losing power.

The thermostat has been sticking, and needs to be replaced after only 30,000 miles.

P0128 code for thermostat issue. Fans run after shutting car off. Steering assist reduced message. Check engine light. Chevy knows this is a common issue. This needs to be investigated ASAP.

2020 Chevrolet Blazer, 19900 miles, lightly driven the radiator seam is leaking coolant, which appears to be a known issue as there are numerous complaints on various websites and forums. The vehicle is now unreliable due to an overheating risk.

I am writing to inform the appropriate authorities of the issues that I’ve continually had with my 2023 Chevrolet Blazer. It has come to my attention that the aforementioned vehicle will need a new transmission and possible engine repair currently totaling at just over 6,000 dollars in repair costs. When I was provided with the total repair cost I was informed by the certified service representative that this was a common issue for the Blazer model and that gm was aware of the ongoing issue. I’ve reached out to gm with my concerns regarding this vehicle and the fact that this is an issue that has in prior dates prompted recalls for Blazer models from the year 2020-2024. I have because of the transmission defects/ failures been stranded and unable to shift gears required for proper motion of the car. To which I am sure you can understand the public safety risk of an inoperative transmission. I have taken the car in for service concerning the transmission on 3 separate occasions within the last 10 days and was told by prior service technicians that “ no problems were visible” leading to the total breakdown of the transmission. I reached out to gm and told them of my wish to return the leased vehicle early due to my fears of now driving and operating the car and was told that I was not eligible for a buy back. Gm is maintaining its stance of no liability and I am seeking outside help from this governing agency to ensure that repair costs are fully covered for this defective product.

Was getting a steering assist reduced error code. Auto stop quit functioning and air conditioning stopped cooling. Engine sounded like a jet. P 0128 thermostat error code came up and had to be replaced. I see lots of similar complaints. Cost me $700.

At routine oil change dealer noticed radiator was leaking. 60,840 miles took it to an independent repair shop who confirmed radiator needed to be replaced. Has also seen same on other 2021 Blazers. No visible signs of leaking (fluid on garage floor) or warning indicators. No recall issued on this, however, seems to be a common problem on 2021 Blazer based on chevy forums. Due to safety issues, vehicle is currently in shop for the needed replacement repair.

The contact owns a 2022 Chevrolet Blazer. The contact stated that upon stopping at a red traffic light, the vehicle's auto start/stop system activated and turned the engine off. The warning message "brake system failure - esc- steering assistance reduced". The driver was able to pull to the shoulder of the roadway and turn the vehicle off. Upon restarting the vehicle, the vehicle returned to normal functionality, but the failure recurred. The check engine warning light was illuminated. The vehicle was not diagnosed or repaired by the dealer or an independent mechanic. The manufacturer was notified of the failure, and a case was filed. The contact was referred to the NHTSA hotline for assistance. The failure mileage was 121,000.

Coolant smell when parked with engine running. Radiator was replaced under warranty at ~16,000 miles coolant smell again ~49,000 miles. "pressure tested at dealership with following notes: "found radiator core on driver side seeping/leaking. Provided estimate on cost. No repair made during this visit. " many forums on 2021 Chevrolet Blazer note poor quality in radiators. This would be the 3rd radiator in less than 50,000 miles on the vehicle.

2023: 16k miles, the Chevrolet Blazer in questions transmission went out; thus requiring it to be brought into the dealership for repair; it was "repaired" and given back to us. A few days after said repair, I was driving it with my son in the vehicle, and the transmission went out while on the highway. I was almost hit from behind as I limped it to the side of the road. A brand new transmission was put in. During this time, there was also issues with the brakes where they were making noises. 2025: Blazer check engine light came on. On the way to get it diagnosed, it began to overheat; we were limping it to the side of the road when it stated "engine overheating, vehicle turning off". The safety system for shutting down when overheating worked, however, I was in the roaad again. Thus putting me in danger of being hit. We just received notice from the dealership that it is (as of this moment) a cooling fan, ac pressure switch, thermostat, and a cracked radiator. We are waiting on the technicians to finish checking it to see if there are any other issues.

Warning message indicating steering assist system reduced, engine fan running non-stop, ac blowing hot air, temperature gauge not registering/stuck on cold. Faulty engine temperature sensor and thermostat.

Diagnosed as a bad thermostat. Ac not working. Steering assist issue. Temp gage not working. Car is out of warranty.

Intermittent dash warning: "action required. Steering assist is reduced. Drive with care. " power steering is sluggish when this happens. Having this happen while driving could be dangerous. Only stays on for a few minutes then goes away. This started with only 10k miles and has been continuing for 2+ years. Based on what I've read online, this is a known issue with the thermostat and/or coolant temp sensor. Dealership refuses to fix it unless it's throwing a code while in the dealership. Of course, it never throws the code while at the dealership.

On the way to work my car said “driver assist is stopping drive with care” about 2-3 times. Upon getting out of my car it sounded like my car was still running. I turned it off and on a few times and it still sounded that way. I had to go inside or I would be late so about 20 minutes later I was able to come back and check on it and the noise stopped. It was coming from the hood. Upon googling I figured it was something to do with a faulty temperature gauge which correlated with the signal from the car as well as the sounds. It seemed like this is a very common occurrence for these cars. I called the dealership and they said they fix these everyday and the man knew exactly what was wrong before I could even finish describing it. Unfortunately I don’t know the cost of this and have already had several other things to repair in my home recently so this will be detrimental to my finances if this isn’t covered. On the way home it did it again along with no ac in the 90 degree heat and then the engine light came on. We had to open the hood and leave the garage door open to prevent any possible harm that may do in the garage. This could be very dangerous for me as I drive my car everyday to work and can’t afford to rent a car for several weeks while this one isn’t working. And I’ve only had it for 6 months. Now my husband and I have ti figure out how we are each getting to work with one car until we get this fixed or we borrow a family members car.

Vehicle gear shifter is stiff and difficult to pass from park to drive--the gear shifter gets stuck in neutral often. The entire dash and instrument cluster goes black during driving and will not come back on until hours later even after the vehicle has been turned off and back on. This has caused me to be unable to see my speed, turn signals, fuel gauges or any engine controls. This leaves me unable to operate or control my vehicle. This is a huge safety issue when driving as I am unable to determine my speed or see any of my vehicles controls or warnings. The front passenger seat motor has a horrible vibration and struggles to adjust the seat properly. I have contacted multiple dealerships on multiple occasions regarding these issues and have been told that the extended warranty will not cover any of these issues although I was told it would when I purchased. Chevy has refused to offer assistance with towing the vehicle to a dealership when the cluster stops working and encourages me to drive a vehicle that is not operational. The service manager at one location told me this was a known issue with the vehicle.

I am reporting a serious safety concern involving my 2021 Chevrolet Blazer, which experienced brake failure while driving, without any warning lights or diagnostic alerts from the vehicle’s onboard system. This created a highly dangerous situation for myself and others on the road. Prior to this incident, I brought the vehicle to the dealership after consistently hearing squealing or screeching noises when braking. The issue was dismissed and attributed to a change in federal regulations limiting the use of copper in brake pads—without any further inspection. This resulted in a missed opportunity to diagnose what appears to be a deeper mechanical failure. After the brake failure, service technicians discovered that the vacuum pump had failed, which impacted braking performance and also caused engine damage. While I’ve since learned that gm has acknowledged vacuum pump failures in several vehicles manufactured between 2014–2018 (via formal recalls), the 2021 chevy Blazer is not currently included in those campaigns however, the symptoms and outcome I experienced are strikingly similar to the documented defects in older gm models. The lack of early diagnostic detection, coupled with dealership dismissal of clear warning signs, signals a potential emerging safety defect in this newer model that may not yet be officially recognized. Given the safety-critical nature of the braking system and the failure of both mechanical and procedural safeguards, I strongly urge NHTSA to investigate whether this issue is more widespread in recent gm models, including the 2021 Blazer. Other consumers may be at risk without knowing it.

At startup, I would receive a message that said, steering assist reduced. There were no check engine lights or warning lights. My air conditioning stopped working, and my temperature gauge on the dash remained at cold. I also noticed the radiator fans were on full blast, continuously. I called the dealer, and they weren't sure what was causing that. I told them I was getting codes #u0401 & p0128. They asked me to clear the codes to see if they returned. I cleared the codes, but they returned immediately on restart of the engine. I'm going to replace the thermostat but I didn't understand the #u0401 code, so did further research. I found 2017 bulletin #17-na-158 which seamed relevent to my issues, and vehicle fitment that confirmed my 2019 chevy Blazer is included. I then came to find that the un-shielded low voltage wires for the coolant temperature sensor are routed through the same harness as high voltage coil wiring. Some of us know that emi will affect low voltage signals. As an hvac system designer, I know that un-shielded low voltage communication wiring cannot run parallel two line voltage power wiring. The effects are not continuous, but definitely reoccurring. I also understand there has not been a recall for this issue which surprises me. I can replace the thermostat even in its difficult position, but I don't feel comfortable in separating the low voltage wiring from the harness. I understand that dealers who are aware of this issue, charge a hefty fee to do so. It's definitely one that I can't afford.

The contact owns a 2020 Chevrolet Blazer. The contact stated that while driving at an undisclosed speed, the steering wheel became inoperable. The contact stated that the steering wheel became difficult to turn with a reduced steering message displayed. The vehicle was taken to the dealer, where it was diagnosed that the thermostat had failed, which caused the steering wheel to fail, and needed to be replaced. The vehicle was not repaired. The manufacturer was made aware of the failure. The approximate failure mileage was 54,000.

The contact owns a 2020 Chevrolet Blazer. The contact stated while driving approximately 45 mph, the instrument cluster went black, and the vehicle stalled. The contact stated that there was no warning light illuminated or an audible chime heard. The contact stated that several attempts were needed to restart the vehicle. The vehicle was restarted, and the message "vehicle in transport mode" was displayed. The contact stated that the failure was intermittent but reoccurred. The contact stated that the vehicle was not taken to a dealer or independent mechanic to be diagnosed or repaired. The manufacturer was informed of the failure and referred the contact to the NHTSA hotline for assistance. The failure mileage was approximately 92,000.