NHTSA Complaint #11709368 — 2025 GMC SIERRA 1500

The contact owns a 2025 GMC Sierra 1500. The contact stated that while driving at 35 MPH, there was an abnormal knocking sound coming from the engine. No warning lights were illuminated. The vehicle was towed to the dealer, where it was diagnosed with a rough idle code, and that the thermostat coolant housing had failed. The contact was provided DTC codes: B1A76 with failure Code 0X15 (pending), P05D, U0075, U0101, U0146, U020C, U0265, U1614, and U1616, and the codes were active. The vehicle was repaired. The contact picked up the vehicle from the dealer after hours, and when the contact started the vehicle, the abnormal knocking sound was still coming from the engine. No warning lights were illuminated. The contact stated that when the A/C was turned off, the abnormal sound ceased. Additionally, the contact performed the oil changes on the vehicle and noticed that the engine was consuming an excessive amount of engine oil. The contact stated that there were no oil stains on the ground. The contact needed to add oil every 800 to 1,000 miles driven. The vehicle was taken to O'Reilly's Chevrolet, located at 6160 E Broadway Blvd, Tucson, AZ, for a diagnostic test, and it was determined that the air compressor had failed. The vehicle was not repaired. The vehicle remained at the dealer pending the repair. The contact stated that when the A/C was activated, the knocking sound in the engine compartment returned. The manufacturer was not made aware of the failure. The failure mileage was approximately 18,000.