2021 Chevrolet Blazer

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)

NHTSA ID

11764895

Incident

Sep 13, 2026

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.

NHTSA ID

11764652

Incident

Sep 16, 2026

The contact owns a 2021 Chevrolet Blazer. The contact stated that a technician identified a radiator leak during an emissions test after smelling an abnormal coolant odor. The technician confirmed that the coolant had leaked from the vehicle. Prior to the discovery by the technician, the contact’s husband observed white smoke coming from the engine. The fluid levels were checked and were normal at that time despite the smoke. Additionally, the contact stated that the message "Steering Assist Reduced" was displayed on the instrument panel prior to the failure. The vehicle was not repaired. The dealer provided an estimate for the repair with 15% goodwill assistance towards the cost. The manufacturer was notified of the failure. The vehicle was not repaired. The failure mileage was 46,860.

NHTSA ID

11763020

Incident

Aug 1, 2026

Mileage

46,860 mi

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.

NHTSA ID

11761571

Incident

Aug 19, 2026

Mileage

68,400 mi

My 2021 Chevrolet Blazer RS equipped with the 3.6L LGX V6 experienced catastrophic engine failure at approximately 90,200 miles. The vehicle had no prior warning. The dealer diagnosed the timing chain / lift/ cam damage. I am requesting investigation into whether this represents a safety or durability defect affecting other vehicles

NHTSA ID

11759058

Incident

Aug 5, 2026

Car will not crank, stalled while cranked, throws code P023F

NHTSA ID

11758918

Incident

Aug 15, 2026

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.

NHTSA ID

11758482

Incident

Feb 2, 2026

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.

NHTSA ID

11758374

Incident

Aug 20, 2026

This preliminary information advises a dealer on how to email GDS2 session logs into Technical Assistance.

This Preliminary information communicates to dealer to perform a MEC reset for wireless projection issues

PI to help diagnose A/C concern

This Preliminary information communicates an issue with an OTA pending message still displayed after an OTA event and how to reset/clear the message.

Pi created to provide GM dealers with information on gathering information for projection issue

This Preliminary information communicates to dealer to perform a MEC reset for wireless projection issues