I am writing to formally document serious engine defects I have experienced with my 2021 Chevrolet Tahoe equipped with the 5.3L L84 V8 engine. 1.Crankshaft Failure: My Tahoe suffered a catastrophic crankshaft failure that required major repair/replacement. I am aware that GM has recalled certain vehicles equipped with the 6.2L L87 engine for crankshaft and rod-bearing defects. Based on my experience, the same or a very similar defect has also occurred in my 5.3L engine, which is currently not included in that recall. 2.Valve Lifter Failure: In addition, my vehicle has suffered from valve lifter collapse-?"a well-documented problem in 2021-?"2022 GM trucks and SUVs with both the 5.3L and 6.2L engines. This caused severe misfiring, drivability issues, and expensive repair needs. Why this is a concern: -??Both failures occurred well before what would be expected of a modern engine. -??The crankshaft failure raises a safety risk: sudden loss of propulsion while driving could lead to accidents. -??The lifter issue is widely reported by other owners and has been the subject of GM service bulletins. -??Taken together, these problems suggest systemic defects in the 2021 Tahoe-??s 5.3L engine that have not been adequately addressed by GM. Requested Action: -??I ask GM to extend recall and warranty coverage to include the 5.3L L84 engine in addition to the 6.2L L87. -??I ask NHTSA to consider investigating whether the scope of the current 6.2L recall should be broadened to include 5.3L engines, given failures like mine. -??At minimum, I request assistance in covering repair/replacement costs for both the crankshaft and lifter defects, which are clearly not due to normal wear and tear. Vehicle details: -??Year/Make/Model: 2021 Chevrolet Tahoe -??Engine: 5.3L V8 L84

- Jackson, GA, USA

1. What component or system failed or malfunctioned, and is it available for inspection upon request" Answer: The vehicle-??s 6.2L L87 V8 engine suffered a sudden internal mechanical failure involving the connecting rod, rod bearings, and crankshaft assembly, resulting in catastrophic engine damage. The failure mode is consistent with the defect described in GM Recall N252494001. The engine and all damaged components are fully available for inspection upon request. 2. How was your safety or the safety of others put at risk? Answer: The engine failed without warning while the vehicle was in motion, causing an immediate loss of propulsion. This created a hazardous situation where the vehicle could no longer accelerate or maintain speed in traffic, increasing the risk of a rear-end collision or loss of vehicle control. GM-??s own recall documentation identifies this exact failure mode as a significant crash risk, and that same hazard occurred in my case. 3. Has the problem been reproduced or confirmed by a dealer or independent service center? Answer: Yes. A service technician confirmed catastrophic internal engine failure consistent with connecting-rod or crankshaft damage. The dealer also verified that the engine is inoperable and requires full replacement. 4. Has the vehicle or component been inspected by the manufacturer, police, insurance representatives or others? Answer: No, the engine failed while in motion and was taken to the closest mechanic. Inspections by an insurance representative or manufacturer representative can be arranged. The vehicle and damaged engine remain available for further examination. 5. Were there any warning lamps, messages or other symptoms of the problem prior to the failure, and when did they first appear" Answer: No. There were no warning lamps, diagnostic messages, or drivability symptoms prior to the catastrophic engine failure. The failure occurred suddenly and without any advance indication. All service records are available

- Hampstead, NC, USA

The contact owns a 2021 Chevrolet Tahoe. The contact stated that while driving at 70 MPH, the vehicle failed to accelerate as intended while depressing the accelerator pedal. The message -??Service Electronic Stability Control" was displayed, and the traction control warning light and the check engine warning light were illuminated. The failure persisted while driving, and the vehicle failed to exceed 50 MPH. The vehicle was taken to an independent mechanic who diagnosed that the lifters had failed, the camshaft had failed, and there was a misfire in cylinder #5. The vehicle was not repaired. The vehicle was towed to the residence and had not been driven since. The manufacturer was not notified of the failure. The failure mileage was approximately 143,000.

- Staunton, VA, USA

The rear differential makes a rubbing or humming noise when turning left/right at slow speed especially when it-??s cold.

- Plantcity, FL, USA

I am submitting this complaint to the National Highway Traffic Safety Administration (NHTSA) regarding a sudden engine failure in my 2021 Chevrolet Tahoe equipped with a 6.2L V8 engine, which posed a serious safety risk. I was driving on the highway at approximately 65 mph with cruise control engaged. Suddenly, the vehicle lost all power, disengaging the cruise control, and the check engine light began flashing rapidly. I managed to exit the highway safely. While stopped at a traffic light, preparing to turn into a nearby repair shop, the car started shaking violently from side to side, making it difficult to control. I took the vehicle to a Firestone shop and a local Chevrolet dealer, both of which diagnosed massive engine failure and indicated that the engine will most likely need to be replaced. The symptoms I experienced-?"sudden loss of power at highway speeds, flashing check engine light, and violent shaking-?"are in line with issues reported in other GM 6.2L engines that have been recalled. ? For whatever reason, my 2021 Tahoe, which falls in the middle of the affected model years for these recalls (e.g., GM recall N252494001 for 2021-2024 vehicles with 6.2L V8 engines due to defects in connecting rods and crankshafts leading to engine damage and loss of propulsion), is not included under the broader GM 6.2L engine recall, ? although I experienced very similar issues. The biggest safety concern was the engine essentially losing power at highway speeds, which could have led to a crash. I urge NHTSA to investigate and expand coverage if necessary to ensure public safety.

- Fulshear, TX, USA

The contact owns a 2021 Chevrolet Tahoe. The contact stated that while driving at an undisclosed speed, several unknown warning lights illuminated. In addition, the contact noticed an abnormal ticking sound. The vehicle was towed to an independent mechanic, where the vehicle was diagnosed with a misfire in cylinder #7. The independent mechanic checked the spark plugs and other unknown parts for failure; however, there was no evidence of a failure. The contact was informed of a valve lifter failure. The contact was informed that the valve lifter and possibly the push rods and camshaft needed to be replaced. The vehicle was not repaired. The manufacturer was made aware of the failure but provided no assistance. The contact referenced Technical Service Bulletin: N212353840; however, the VIN was not included. The contact was advised to contact the NHTSA Hotline to report the failure. The failure mileage was approximately 87,893.

- Mansfield, TX, USA

My tahoe is throwing a low engine oil code and burns through about 2 quarts of oil in between oil changes. other tahoes of the same year make and model have been recalled for the same issue but mine was not.

- Meadville, PA, USA

We have experienced a loss in power that is accompanied with an audible engine knocking sound. The loss of power affected our ability to safely merge into the highway.

- Victor, NY, USA

On the morning of 1 Oct, I had left the house here in Cedartown GA to head to a meeting in Atlanta with a customer. I had started the truck 15 minutes before departing just as we have always done to our vehicles over the years to allow them to warm up properly. I departed Doyle Rd onto Hwy 27 South heading towards interstate 20. About 15 miles from the house I was at a steady cruise speed of 45 MPH, no traffic, acceleration or deceleration and the stability control system light came on, one second later the engine light came on and the engine all of a sudden started making a loud grinding and clunking noise. I was on the inside lane so let the car pass next to me and started to pull over onto the shoulder of the road. I immediately shut off the truck, popped the hood and got out to inspect what might have happened. There was no smoke, I checked all the fluids and all were at the normal ranges. The engine oil was at its full mark as well. The oil was just changed a month early and still of the same color as it was new. After checking, I got back on the truck, attempted to start and it ran for a few seconds then I immediately shut it off after hearing again the loud noise. A Polk county police officer stopped to check on me and offer assistance as well as some tow companies to call. Eventually after about at hour a tow truck showed, we tried to momentarily start the vehicle so it could be put in neutral but the engine had locked up. I-??m glad I got off the road when I did, otherwise I feel I could have been driving and experienced that sudden lock up and loss of control which could have been a serious accident with log trucks up and down that highway all day long. This vehicle is my wife-??s primary vehicle and always has been maintained to a T just like all of our GM vehicles have. My daughter just graduated and drives our passed down 2005 Tahoe with over 300k miles that we bought in 2006. This has never happened to us and I feel it is a serious safety issue on the 6.2

- Cedartown, GA, USA

The contact owns a 2021 Chevrolet Tahoe. The contact stated that while his wife was driving at undisclosed speeds, there was an abnormal ticking sound coming from the vehicle. The check engine warning light was illuminated. The vehicle was taken to the local dealer, where it was diagnosed, and determined that the cylinder #1 left side lifters and push rod had collapsed. The lifters and push rod assembly were replaced. The contact stated that on a separate occasion, while driving at undisclosed speeds, there was an abnormal ticking sound coming from the vehicle, and the check engine warning light illuminated. The vehicle was taken to the local dealer, where it was diagnosed, and determined that cylinder #4 lifters had detached, and the push rod was bent. The vehicle was repaired. The contact stated that the engine was consuming an excessive amount of engine oil. The contact related the failure to TSB: 15-06-01-002A. The dealer and manufacturer were not made aware of the failure. The failure mileage was approximately 12,400.

- Crosby, TX, USA

We just recently had the cam shaft and lifters replaced, as the vehicle began experiencing a knocking sound. The repair was supposedly completed, and they gave the truck back. We took the truck back in within a week, bc we continued to hear the sound. They sent it back saying they didn-??t hear anything after test driving it. Over the weekend the car shut off after beginning to shake uncontrollably. Now supposedly the camshaft bearing is gone, and the truck experience engine failure. I spoke with someone previously, as the issue being repaired hundred thousands of cars were recalled for the same issue. I was told that it wasn-??t on the same line, even though my truck was experiencing the EXACT issue and fell under the years. We were placed back on the road with our family, with a vehicle

- Miami, FL, USA

Driving car, suddenly when accelerating engine light started flashing, car was shaking and making knocking noise

- Fellsmere, FL, USA

2021 to 2024 has had countless problems with the 6.2l engine. General Motors has put a stop of sale on vehicles with this engine. When I purchased the car the wrong oil was in the car which always burned off with 2 months after an oil change. They figured out the right oil but the damage has already been done.

- Philadelphia , PA, USA

I am writing to formally document serious engine defects I have experienced with my 2021 Chevrolet Tahoe equipped with the 5.3L L84 V8 engine. 1.Crankshaft Failure oMy Tahoe suffered a catastrophic crankshaft failure that required major repair/replacement. oI am aware that GM has recalled certain vehicles equipped with the 6.2L L87 engine for crankshaft and rod-bearing defects. oBased on my experience, the same or a very similar defect has also occurred in my 5.3L engine, which is currently not included in that recall. 2.Valve Lifter Failure oIn addition, my vehicle has suffered from valve lifter collapse-?"a well-documented problem in 2021-?"2022 GM trucks and SUVs with both the 5.3L and 6.2L engines. oThis caused severe misfiring, drivability issues, and expensive repair needs. Why this is a concern: -??Both failures occurred well before what would be expected of a modern engine. -??The crankshaft failure raises a safety risk: sudden loss of propulsion while driving could lead to accidents. -??The lifter issue is widely reported by other owners and has been the subject of GM service bulletins. -??Taken together, these problems suggest systemic defects in the 2021 Tahoe-??s 5.3L engine that have not been adequately addressed by GM. Requested Action: -??I ask GM to extend recall and warranty coverage to include the 5.3L L84 engine in addition to the 6.2L L87. -??I ask NHTSA to consider investigating whether the scope of the current 6.2L recall should be broadened to include 5.3L engines, given failures like mine. -??At minimum, I request assistance in covering repair/replacement costs for both the crankshaft and lifter defects, which are clearly not due to normal wear and tear. Vehicle details: -??Year/Make/Model: 2021 Chevrolet Tahoe -??Engine: 5.3L V8 L84

- Chattanooga, TN, USA

I drive a 2021 Chevrolet Tahoe. This occurrence has happened on three separate occasions and each time it was raining outside. The first occurrence, my vehicle was running and parked in the rain after driving approximately 5 miles. While parked my check engine light came on with a series of warnings: service ECS, service traction control, forward collision system unavailable, reduced acceleration drive with care. Two days later it went away. The second occurrence, I was driving in the rain for approximately 22 miles and briefly parked with my vehicle running. I then turned out of a parking lot and began to accelerate to speed up and the check engine light came on along with all the same messages, this time my vehicle acceleration had seized and wouldn-??t go faster than 30 MPH. I slowly drove back to the parking lot and turned the vehicle off to let it sit, disconnected the battery and reconnected, and the issues went away. The third occurrence, I was driving on the highway in the rain for approximately 10 miles, I went to merge into a right hand lane, I took my foot off the acceleration peddle to slow down for the merge and as I slightly turned the wheel to the right, my vehicle spun out three times, throwing the back end of the Tahoe into the inner highway wall, which spun me again to face the right direction, next to a highway exit. I then went to accelerate to exit the highway but noticed my vehicle would only coast and realized my engine had cut out at some point. I started the vehicle and exited the highway and parked in a parking lot only feet away from the exit. After I parked I noticed all the same warning lights came back on. Each occurrence happened on [XXX], [XXX], [XXX]. My vehicle was towed to Gunn GMC Collision Center in Selma, Tx and will be looked at on September 3, 2025 around 8:00am. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

- New Berlin, TX, USA

The affected systems are the power train, engine, and electrical. My 2021 Chevrolet Tahoe experienced failures consistent with GM Technical Service Bulletin 21-NA-149 (engine wiring harness chafing) and the conditions outlined in Recall N232404190 (valve body failure, November 2024). Beginning in March 2025, the vehicle displayed warning lights and messages including Check Engine, Traction Control, Service Transmission, and limp mode (Reduced Acceleration -?" Drive with Care). The vehicle shifted erratically, lost power, and occasionally failed to accelerate, creating a serious safety hazard at highway speeds. These problems were documented at AutoNation Chevrolet South Clearwater, where multiple diagnostic trouble codes (P0700, P0717, P2714, P2716, P0706, and U-codes) were recorded but not properly investigated. No test drive was performed despite being claimed by the service technician, and the applicable TSB was not referenced. By July 2025, the condition worsened into a complete transmission failure, with additional codes (P0700, P077C, P17F6, P17FB, P1872). The dealer-??s estimate required a full transmission replacement at nearly $10,000. GM reviewed the case through its internal Policy Evaluation Tool and increased goodwill assistance from 15% to 40%, while AutoNation contributed only $500. GM-??s partial contribution confirms the defect is recognized, yet this VIN remains excluded from the official recall. This issue placed my family and other motorists at significant risk, as sudden loss of power and shifting failures occurred during normal driving conditions. Dealer records, GM documentation, and photographs of warning messages are available. I request that NHTSA expand Recall N232404190 to include affected VINs such as mine, since the symptoms, diagnostic codes, and confirmed failures match exactly what GM has already identified as a known safety issue.

- Odessa, FL, USA

The affected components are the electrical system, engine, and power train. In March 2025, my 2021 Chevrolet Tahoe displayed multiple warning lamps across the dash, including traction control and check engine lights. The vehicle shifted erratically and sometimes entered limp mode. I brought the vehicle to AutoNation Chevrolet South Clearwater for inspection. The dealer replaced the battery, dismissed my concerns, and stated that a test drive was performed, but the mileage in and out on the invoice was identical, showing it never actually occurred. Diagnostic trouble codes (P0700, P0717, P2714, P2716, P0706, and multiple U-codes) were present but were not fully investigated. A GM Technical Service Bulletin (21-NA-149, December 2022) covers these exact symptoms (caused by engine wiring harness chafing), but it was never referenced or applied. Because the problem was not addressed, the condition worsened. By July 2025, the vehicle suffered a complete transmission failure. At that point, the dealer confirmed the issue, documenting transmission slipping, shuddering, noise, and additional codes (P0700, P077C, P17F6, P17FB, P1872). GM increased its goodwill contribution from 15% to 40% of the $9,925 repair cost, while AutoNation offered only $500 despite their role in the missed diagnosis. Safety Risk: My family and I were at risk each time the vehicle stalled, lost power, or shifted erratically while driving, including at highway speeds. These failures created a significant risk of collision. The drivability problem was not properly confirmed in March 2025 despite multiple codes being present. By July 2025, the dealer acknowledged and confirmed the transmission failure. The vehicle remains available for inspection, and I have retained all invoices, diagnostic reports, and communications with GM and the dealership.

- Odessa, FL, USA

When driving the car just stops losing power then the car immediately shuts down and stops driving. I had to call a tow truck when it-??s taken to the dealership the fuel pump power control module is faulty. This is a 2021 Tahoe they had to replace the fuel pump, power control module, and this vehicle should not have to be replaced. Chevrolet/GMC knows that these modules will make the vehicle stop wherever it is driving. I happen to be on a freeway going 70 mph and could have been killed. They have not put a recall out to have these modules replaced in any SUV. This is a danger for any driver on the road. This is a lawsuit waiting to happen for people. You know that they are aware this is happening because they paid for the tow and replaced this part that is not warranty now for free. Yes, great that it was paid for but thankful I did not lose my life as I could-??ve been rear ended when my car shut down going that fast in the middle of the freeway I am begging that they please put a recall so no one gets injured or killed.

- Houston , TX, USA

Leaving the stoplight, all the sudden the dash read service ECM in the motor started clanking. Took it to the dealership where they told me the cam and lifters were bad and said we might as well get a new motor $17,000. And not approved by extended warranty, crooks.

- Yukon, OK, USA

To Whom It May Concern, I am writing to formally report serious defects with my 2021 Chevrolet Tahoe (VIN: [XXX] ) and to request assistance with repair costs. Approximately six months after purchase, when the vehicle had about 22,000 miles (I bought it used with around 19,000 miles), the battery and electrical system failed. I brought it to the dealer and was told there was no issue; they only performed a jump start. Two days later, the vehicle broke down in the middle of the road. I had to pay for a tow truck and replace the battery completely out of pocket. More recently, at about 92,000 miles, the vehicle developed severe engine problems. A certified mechanic diagnosed collapsed AFM lifters and camshaft damage. The repair requires OEM GM parts and costs approximately $4,500. This issue is widely reported by other GM owners with 5.3L AFM engines and is known to be a manufacturing defect, not a maintenance problem. Please note that my Tahoe has been well maintained, with oil changes always performed on time and using the correct oil and service intervals recommended by GM. Despite this, the vehicle has experienced repeated and costly failures that create unsafe driving conditions. I kindly request that GM review my case and provide assistance with covering the repair costs or reimbursement, given that these issues are the result of known defects and not owner neglect. I look forward to your prompt response. Sincerely, [XXX] [XXX] 33032 [XXX] [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

- Homestead, FL, USA