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What 17 owners told NHTSA about the 2018 GMC Sierra Denali

These are the actual owner complaints behind this car’s reliability verdict, filed with the federal government, unedited. They’re unverified reports, not confirmed defects: read them as leads for your pre-purchase inspection, not a diagnosis.

All (17)Crash / fire / injury (1)Engine (5)Body & structure (4)Brakes (4)Lights (3)Steering (3)Electronic Stability Control (esc) (2)Transmission & drivetrain (2)Suspension (1)Wheels (1)

4 of 17 complaints match · Body & structure · clear filters

Mar 11, 2026Body & structureEngine

The contact owns a 2018 GMC Sierra 1500 Denali. The contact stated that while driving at an undisclosed speed, and while the vehicle was parked, the running boards unexpectedly lowered. Additionally, there was oil leaking from the vehicle, and the check engine warning light was illuminated. The vehicle was taken to the dealer, where it was diagnosed with camshaft failure. The contact was informed that the camshaft needed to be replaced. The vehicle was repaired. The manufacturer was made aware of the failure. The approximate failure mileage was 107,000.

NHTSA ODI 11723657

Jun 29, 2023Body & structure

The contact owns a 2018 GMC Sierra 1500 Denali. The contact stated while exiting a parking lot, the passenger’s side running board detached from the vehicle causing minor damages to the passenger’s side of the vehicle. There was no warning light illuminated. The dealer was contacted but provided no assistance and advised the contact that the running board needed to be replaced. The vehicle was not repaired. The manufacturer was contacted but provided no assistance. The failure mileage was 35,000.

NHTSA ODI 11529615

Apr 5, 2021Body & structure

HOOD VENT FELL OFF WHILE DRIVING NORMAL SPEEDS ON THE HIGHWAY AND HIT THE CAR BEHIND ME. I FEEL THAT THE CHEAP PLASTIC IS DEFECTIVE AND COULD CAUSE A PROBLEM WITH THE PART GOING AIRBORNE AT HIGH SPEEDS AND HITTING OTHER CARS.

NHTSA ODI 11406471

Jun 21, 2020SuspensionBody & structure

THE REAR END MAKES NOISE WHEN TURNING AND SOMETIMES STOPING. WHEN WEIGHT IS PLACE ON BED THE REAR END MAKE NOISES. SOMETHING IS WRONG IN THE REAR END OF THIS TRUCK. WHEN TRUCK IS MOVING AND TURNING YOU CAN HERE THE NOISE.

NHTSA ODI 11329880

Working with the data? Download all 17 complaints as CSV · fetched from NHTSA July 20, 2026

How to use these: a complaint is one owner’s report, filed voluntarily and published unverified. Patterns matter more than any single story. If several owners describe the same failure at similar mileage, put that system at the top of your pre-purchase inspection list. Back to the full 2018 GMC Sierra Denali verdict →