GMC Complaints

MEMORANDUM To: National Highway Traffic Safety Administration (NHTSA) Subject: Safety Defect Report – 2019 GMC Yukon Denali 6.2L V8 (L87) with AFM/DFM I am reporting a serious and recurring safety defect involving my 2019 GMC Yukon Denali equipped with the 6.2L V8 L87 engine and GM’s AFM/DFM system. In the past twelve months, I have experienced two separate engine failures, both occurring at highway speeds and both involving valve-train/VLOM failures on the same side of the engine. In each incident, the vehicle suddenly lost power, misfired violently, and became unable to maintain speed. This created an extremely dangerous situation for my family. One failure occurred while my wife was driving; the other occurred while my [XXX] son was driving. Both were forced to maneuver across high-speed traffic with a failing engine to reach the shoulder. These events posed a clear risk of a high-speed crash, injury or even a fatality. There are hundreds—possibly thousands—of documented complaints from owners of GM vehicles with AFM/DFM-equipped engines reporting the same issues: collapsed lifters, valve failures, VLOM malfunctions, and sudden loss of propulsion. These failures often occur without warning and show a consistent pattern across multiple model years and engine variants, including the L87. The sudden loss of power at highway speeds represents a significant safety hazard. The frequency of similar reports suggests a systemic mechanical defect rather than isolated incidents. I respectfully request that NHTSA open a formal investigation into AFM/DFM-related failures in GM’s L87 and related V8 engines, with a focus on lifter, valve, and VLOM failures that lead to abrupt engine shutdown. Appropriate safety action, including a mandatory recall, should be done immediately to prevent potential injuries or fatalities. I will provide repair documentation, service reports, and other additional information. [XXX] , Esq. [XXX] [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B

My vehicle has developed a leak in the plastic fuel tank at the junction of the fill hose connection and the body of the tank that is causing release of flammable vapors and liquid gasoline underneath the vehicle and causing failure of emissions systems. These vehicles have a rampant and long-standing reputation for developing leaks in their plastic fuel tanks at this location which cannot be repaired by any normal means available to a consumer. Virtually all of these vehicles eventually develop leaks, which cause release of flammable fuel vapors and raw gasolene releases. Why isn't there a recall on these faulty fuel tanks? The manufacturer only provided a short-term solution for a limited period of time that is no longer available for vehicles that still have the leaking tanks. The condition is dangerous.

Odometer Fraud. The contact purchased a 2016 GMC Acadia. The contact discovered a mileage discrepancy after purchasing the vehicle. The vehicle was a dealer sale. At the time of purchase, the vehicle mileage was 180,000. The contact stated that it was later discovered upon checking the vehicle information settings, that the mileage was 300,000.

GM need to be looked at for faulty Thermostats being put into vehicles. While driving the message "steering assist is reduced " You get to a safe place and shut you car off and the fan still runs. After speaking with my dealer today, he said he has done 7 in last week. And if you look online, everyone especially Acadia models is having this problem. Customers are getting charged alot of money for the repair. To me this is a defective thermostat on GM and needs to be addressed

While traveling to work at 75mph, a sudden an unexpected malfunction of internal engine components caused a loss of propulsion.

My engine is currently being torn down at the dealership.I heard a ticking noise coming from my engine so I took to the dealership I bought it from and when they did their diagnostics and inspection they said it was a connecting rod bearing failure.

This is the 3rd catastrophic engine failure since purchasing this new vehicle from the dealership, the vehicle is currently at the dealership and is available for inspection. The latest diagnostic report has been attached from the dealership for reference. My safety and the safety of others was at risk with each occurrence. The 1st occurred on the interstate when a lifter rod bent causing loss of power with no warning, engine was rebuilt by the dealership. The 2nd occurred on the interstate when a different lifter rod bent causing loss of power with no warning, engine was rebuilt again by the dealership. The 3rd occurred just recently while on a highway. The engine suddenly turned off with no warning. The dash told me to put it into neutral and start again. I had to coast the truck for a long distance after the sudden loss of power in order to attempt to restart the engine. The engine would not start. The diagnostic report from the dealership states "engine is seized tight, maxi fuse is blown, needs engine replacement."

The contact owns a 2021 GMC Sierra 1500. The contact received the recall letter for NHTSA Campaign Number: 25V274000 (Engine and Engine Cooling). The contact called the local dealer, who confirmed there was no information from the manufacturer to move forward. The vehicle was not diagnosed or repaired. The manufacturer was not contacted. The contact had not experienced a failure.

The contact owns a 2017 GMC Sierra 1500. The contact stated that after remote starting the vehicle, upon entering the vehicle, the contact became aware of a burning odor in the interior of the vehicle. In addition, the contact noticed smoke coming from the rear of the vehicle, and the back glass was fractured. The vehicle was taken to the dealer, where it was diagnosed with a failed defrost resistor. The contact was informed that the defrost resistor needed to be replaced. The vehicle was not repaired. In addition, the contact stated that five years prior, a recall repair was performed, and the defrost resistor was replaced under the recall. The manufacturer was made aware of the failure, and a case was filed. The contact was advised to contact the NHTSA Hotline to report the failure. The failure mileage was approximately 109,000.

The contact owns a 2022 GMC Sierra 1500. The contact stated that on several occasions while driving at speeds over 20 MPH, the vehicle began shaking and the transmission shifted prematurely and hard. The contact stated that the check engine, traction control, ABS, transmission, and other unknown warning lights were intermittently illuminated. The contact stated that on one occasion while driving at an undisclosed speed, the brake was depressed; however, the vehicle failed to slow down as intended. The vehicle was not diagnosed or repaired. The manufacturer was not notified of the failure. The failure mileage was approximately 46,000.