NHTSA Complaint #11703710 — 2021 GMC SIERRA 1500

The contact owns a 2021 GMC Sierra 1500. The contact had received notification of NHTSA Campaign Number: 25V274000 (Engine and Engine Cooling). The vehicle was taken to the dealer where an inspection was performed on the engine. The contact was informed that the vehicle had passed the inspection, and the mechanic added a higher viscosity oil, installed an oil fill cap, replaced the oil filter, and updated the Owner's Manual. The contact stated that the remedy failed to address or repair the possible defect with the engine. The contact stated that the remedy resulted in a higher cost for oil changes, and fuel economy had decreased from 21 miles per gallon to 18 miles per gallon. The manufacturer was made aware of the issue and the contact was provided a case number. The contact stated that the vehicle had not been repaired. The failure mileage was unknown.