2021 Chevrolet Blazer Engine Problems

The thermostat malfunctioned causing an error message regarding “steering assist is reduced”. When I parked and turned off, the engine fan continued to run. When car was restarted, the temp gauge inside was stuck at C. Took to dealership and they assessed. They repaired the thermostat under power train warranty, however there was a crack in the radiator (top) resulting in the need for a new radiator. This vehicle had 35,000 miles on it. Upon research online, it seems there are MANY people who have had this same issue and worse. It appears cars produced during COVID era are most affected. Chevy refused to warranty the issue. The dealership offered a small cost reduction (due to our loyalty). The thermostat and the radiator issues seem to be well known by Chevy, they just refuse to accept responsibility. Now we are out thousands of dollars on a basically “new” vehicle.

NHTSA ID

11745926

Incident

May 27, 2026

The thermometer and thermometer sensor are glitching . The engine temp needle will not rise at all, the engine fan will run the whole time driving and then when it is turned off will run for 10 min . Right before this happens a notice shows the guided steering is being limited. I disconnected the battery and it reset , I drove and there were no issues , next time I started my car the engine temp needle stayed down and the van started again. This car has 36k miles on it. I just bought it 2 days before it started happening

NHTSA ID

11745573

Incident

Jun 21, 2026

Went to park car in a park to drop daughter off and it sputtered out and stalled out of nowhere with no warning. I had received a lamp warning very sporadically prior to this and on occasion that stated 'reduced steering assist drive with care' this resulted in heavy steering for that drive until car was shut off and then it would go away and be fine again, fixed the car through Knudtsen Chevy due to a recall about a month before on the issue with the engine being turned off and it thinking it was still hot and still running the fan (even though the car was not running). Knudtsen fixed that issue. Low battery voltage light did not come on however battery was older so had battery installed at park to ensure the issue was not due to the battery. The oil was fresh and showed no issues, changed 2 weeks before fresh oil no issues found during service. When tried to restart the car it would think it would try to start and then sputter out and not stay in idle. Les Schwab left and called a mobile mechanic to bring the computer. Computer was hooked up and it would try to start, however, it would not know it was already running and try to start again on it's own...the codes that came up were the PO101 code came up for Mass Air Flow issue...and then the codes would go in a wild sequence of fail.....mechanic checked for loose connections around air filter, took air filter out and it was clean no issues, checked pipe no visible issues. We walked away and walked around the park to give it some time to sit and then we tried it again and it tried and sputtered out and died again would not stay idling. Then all of a sudden we heard it try to start itself without us trying to start it and it clanked. We hauled it to Knudtsen for a diagnosis. They stated "the motor will not turn this way or that way and it is seized or locked up". This is a 2021 with only 89,000 miles it should have a longer life than this. Please investigate and is there anything we can do to fix it?

NHTSA ID

11734510

Incident

Apr 18, 2026

Both camshaft carriers failed due to a manufacturing defect. According to NHTSA bulletins 21-NA-240 and PIP5755, the oil leak from the cam carrier is caused by improper sealant application during manufacturing. Although the dealer addressed the issue, it was clearly not a problem that arose from normal use. The leak had the potential to worsen and lead to a fire hazard. Chevy of Montebello confirmed the issue and repaired the vehicle for over $7,500. There were no warning signs, as the leak was difficult to detect on the driveway. The low-oil warning light came on the day before we took the vehicle to the dealer.

NHTSA ID

11734437

Incident

Apr 1, 2026

The vehicle had an oil leak from both the left and right camshaft carriers. The dealer confirmed the issue and carried out the necessary repairs. Because the leak was not easily detectable, it could have led to engine failure while driving. There were no warning indicators; only small oil droplets were found on the ground.

NHTSA ID

11731606

Incident

Apr 7, 2026

Once I turn the vehicle off, there is a loud sound coming from the engine area that sounds like a fan. Then the first incident of the fan ongoing after the vehicle was powered off, a battery light was on the internal driver dashboard and stayed on. The battery was recently replaced during 2026 so the battery should not be anywhere near dead, dying, or needing to be checked

NHTSA ID

11730609

Incident

Apr 11, 2026

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.

NHTSA ID

11723904

Incident

Jul 24, 2025

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.

NHTSA ID

11719088

Incident

Jan 7, 2026

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.

NHTSA ID

11716656

Incident

Feb 7, 2026

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.?

NHTSA ID

11714381

Incident

Jan 7, 2026

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

NHTSA ID

11707571

Incident

Oct 28, 2025

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.

NHTSA ID

11705228

Incident

Dec 13, 2025

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.

NHTSA ID

11703542

Incident

Nov 17, 2025

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

NHTSA ID

11701205

Incident

Nov 15, 2025

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 .

NHTSA ID

11699684

Incident

Nov 16, 2025

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.

NHTSA ID

11697313

Incident

Sep 18, 2025

Radiator leak, leaking antifreeze

NHTSA ID

11689652

Incident

Jun 1, 2025

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

NHTSA ID

11688507

Incident

Sep 19, 2025

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.

NHTSA ID

11678892

Incident

Jul 30, 2025

The first incident started on 08/16/2024, 2 days after buying the vehicle used from Dealership. I started getting notifications stating "Service-Front Camera not available" and sure enough, I no longer had a front camera, which then means I no longer have front collision alerts. Then I started getting the random notifications to drive carefully because drivers assistance has been reduced, and now my vehicle's fan will randomly run for up to 30 minutes after it has been shut off and even after a less than 2 mile drive to gas station and back home, it does this. Last item is the vehicle pulls to the right, and I have not hit anything nor has it ever been in an accident prior to my purchase, and my brakes squeal horribly, which shouldn't be happening condidering I haven't even driven the vehicle 5,000 miles in the year since I bought it !

NHTSA ID

11675087

Incident

Aug 16, 2024

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.

NHTSA ID

11667583

Incident

Jun 12, 2025

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.

NHTSA ID

11667243

Incident

Jun 16, 2025

The steering assist stopped working. The defrost stopped working because the ac stopped working. The temp gauge stopped working. Error code P0128. I have since found out all this is caused by a faulty temp sensor.

NHTSA ID

11658646

Incident

May 2, 2025

"Driver Assisted Reduced Use Drive With Care Message" comes on when it is over 70 degrees outside. The temperature gage reads zero, A/C does not work, when the car is turned off the fan runs on high for an extended period of time. Showing code P0128 Used car purchase, came on 3 days after receiving vehicle from the dealership. Reset the code came on again 2.5 weeks later (5/3/2025) when the outside temperature was in the 70's

NHTSA ID

11658644

Incident

Apr 13, 2025

Took 2021 Chevy Blazer to a Chevy dealer for small leak. 25000 miles and dealer said I have a leak in the radiator and needs to be replaced. If I didn't notice the small leak the engine could overheat, and possibly start a fire.

NHTSA ID

11657193

Incident

Apr 21, 2025