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 NHTSA document and evaluate this complaint together with any similar complaints involving this model and model year.

Source: NHTSA complaint ODI #11764652 · view all complaints for this vehicle at nhtsa.gov

The contact owns a 2021 Chevrolet Blazer. The contact stated that while driving 40 MPH, the vehicle stalled and was unable to be restarted. The vehicle was towed to the residence. The husband was a mechanic and discovered the 350-amp fuse failure. The fuse was replaced, and the vehicle was repaired. The dealer was not contacted. The manufacturer was made aware of the failure by phone. The failure mileage was approximately 68,400.

Source: NHTSA complaint ODI #11761571 · view all complaints for this vehicle at nhtsa.gov

Vehicle Information: 2021 Chevrolet Blazer 2.5L engine, VIN [XXX]. Odometer 118000 miles.Description of Incident: While operating the vehicle, the mechanical brake vacuum pump experienced a catastrophic internal failure. The drive gear housing shattered violently without warning, shearing off the end of the connecting engine camshaft. Because this was an instantaneous mechanical failure, the vehicles computer did not trigger any dashboard warning lights, check engine lights, or safe mode protocols prior to the failure.Safety Hazards and Component Damage: First, the total destruction of the vacuum pump caused an immediate compromise to the brake booster vacuum lines, resulting in a sudden, dangerous loss of power braking assistance. Second, the sheared camshaft breached the engine valve cover or head, causing the engines pressurized oil system to instantly dump all engine oil externally onto the ground. Third, shrapnel or violent structural torque from the instant engine seizure punctured or severed the adjacent transmission cooler fluid lines and compromised brake fluid lines, causing total loss of transmission fluid and brake fluid simultaneously.Request for Action: This failure mirrors the exact mechanical defects documented in GM Technical Service Bulletin 21-NA-268 and previous GM vacuum pump recalls like NHTSA Recall 19V-645, which excluded the 2021 Blazer. I am filing this report because the lack of an electronic warning indicator before a catastrophic mechanical brake and engine failure poses an extreme, immediate threat to highway safety. GM must expand recall coverage or issue a Special Coverage Adjustment for this model year. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Source: NHTSA complaint ODI #11764895 · view all complaints for this vehicle at nhtsa.gov

All 4 tires exhibit signs of dry rot impacting the inner sidewalls of each tire. The outer layer is showing significant signs of sidewall separation. There is no sign of damage visible on the exterior side walls, if an inspection was not done on this date 08/20/26 the driver and others would have been at significant risk of injury or death due to catastrophic failure. The worst separation occurred in the front drive / steering tires. While lesser damage was visible on the rear tire the damage was also significant. The driver side rear showed the least damage with only a 2 inch separation. The other 3 tires showed 12 inches or greater separation. Images are available for review.

Source: NHTSA complaint ODI #11758374 · view all complaints for this vehicle at nhtsa.gov

The contact owns a 2021 Chevrolet Blazer. The contact stated that while driving at approximately 50 MPH, the vehicle struck a deer, causing severe damage to the vehicle's front end. The contact stated that smoke was coming from the center of the steering wheel; however, the vehicle's air bags had not deployed. The contact was transported to the local hospital and treated for chest injuries. The vehicle was towed to a local collision center. No further information was available. A Police report was filed at the scene. The cause of the failure was not yet determined. The local dealer and manufacturer were not yet contacted. The failure mileage was 52,661.

Source: NHTSA complaint ODI #11753752 · view all complaints for this vehicle at nhtsa.gov

To whom it may concern, I own a 2021 chevrolet blazer I have been noticing a very large amount of water on the front floor boards since this discovery the windows being moist in the mornings make sence l. The windshield has been replaced several times with no obvious leaks at this location. There is no visible leaks during heavy rain or car washing, the biggest concern i have it if there's moisture I am more likely to develop electrical problems not to mention the moldy smell in the vehicle. I have done extensive research and found this to be a problem with most Chevrolet Blazer's my question is does Chevrolet have a solution to the problem that has found its way to many customers. I would believe with the number of complaints the Chevrolet engineers are working on a solution or a reason for this problem. Thank you, [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Source: NHTSA complaint ODI #11655504 · view all complaints for this vehicle at nhtsa.gov