Most common 2018 GMC Sierra problems
Share of the 17 complaints; one complaint can involve more than one system. "~" is the median mileage when the problem started.
GMC Sierra complaints by model year
Best Sierra years: 2020, 2018, 2009. Years to avoid: 1999, 2000, 1995, 1996, 1997. Compare all years →
What 2018 GMC Sierra owners say
Engine & cooling
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.
Tl* the contact owns a 2018 GMC Sierra denali. The contact received notification of NHTSA campaign number: 19V328000 (engine) however, the part to do the recall repair was not yet available. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. Soechtin motors GMC located at (603 east kingsbury street, seguin, tx 78155, [phone], was contacted and confirmed that the part was not available. The manufacturer was not made aware of the issue. Parts distribution disconnect.
Brakes
On the morning of oct 26, 2020 @ 845 am... I was heading south on 287 in mansfield tx. It was raining hard so I was only going 60 MPH. The car in front of me was going 55 or so. When the rain and wind picked up, the car in front of me abruptly hit its brakes. That's when my truck brakes locked and I began sliding or being pulled to the right. I was in the left lane on the 2 lane highway. Had it not been for god and me, not panicking... I would have crashed! My truck fish tailed twice while I was trying to apply the brakes but... I couldn't stop. I almost put the truck gear in neutral but it was raining so somehow the truck managed to slow down going up a small hill, giving me control back. There were 2 other cars that seen this. I was a nervous wreck! I immediately got off the highway and went to the first gas station I saw and thanked god nothing happened. …
I nearly died when my brakes failed on my 2018 GMC denali this morning. I was only going 60 MPH when another driver cut in front of me, and hit their brakes but when I tried to stop, I could not! I then began swerving from lane to lane because it was raining. Thank god I didn't die and that the person on the right slowed down and moved out the way. The truck seemed to be pulling me to the right. Why I have no idea. But why is GM putting people lives at risk like this? Why are we having to suffer or put our families in jeopardy. This makes no sense. My chest started hurting really bad afterwards, because I was so scared. I was on a 2 lane highway going straight but even that doesn't cause a vehicle not to respond like it did.
Body & structure
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.
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.
2018 GMC Sierra engines & fuel economy
| Engine | Transmission | Drive | MPG city / hwy / combined |
|---|---|---|---|
| 5.3L 8-cyl hybrid | 8-speed automatic | RWD | 18 / 24 / 20 |
| 4.3L 6-cyl | 6-speed automatic | RWD | 18 / 24 / 20 |
| 4.3L 6-cyl | 6-speed automatic | 4WD | 17 / 22 / 19 |
| 5.3L 8-cyl | 6-speed automatic | RWD | 16 / 23 / 19 |
| 5.3L 8-cyl hybrid | 8-speed automatic | 4WD | 16 / 21 / 18 |
| 5.3L 8-cyl | 8-speed automatic | RWD | 16 / 22 / 18 |
| 5.3L 8-cyl | 6-speed automatic | 4WD | 16 / 22 / 18 |
| 6.2L 8-cyl | 8-speed automatic | RWD | 15 / 21 / 17 |
| 6.2L 8-cyl | 8-speed automatic | 4WD | 15 / 20 / 17 |
| 5.3L 8-cyl | 8-speed automatic | 4WD | 15 / 20 / 17 |
EPA ratings. Class: Full-size pickup.
Frequently asked questions
Is the 2018 GMC Sierra a good car?
Based on 17 owner complaints filed with NHTSA, the 2018 Sierra rates better than average: 77% fewer complaints than a typical year of the Sierra at the same age. It is one of the best Sierra years by this measure. Complaint counts don't account for sales volume or individual maintenance, so have any used car inspected before buying.
What is the most common problem with the 2018 GMC Sierra?
The engine & cooling — 5 complaints, 29% of all complaints for this model year. Next are the brakes (4) and body & structure (4).
How many recalls does the 2018 GMC Sierra have?
NHTSA lists no recalls for the 2018 GMC Sierra. You can still confirm with your VIN using our VIN recall check.
What are the best and worst years of the GMC Sierra?
The best years by complaints, compared at the same age, are 2020, 2018 and 2009. Years to avoid or approach with caution: 1999, 2000, 1995, 1996 and 1997. See the full GMC Sierra years comparison.
At what mileage do 2018 GMC Sierra problems happen?
The median mileage reported in complaints is about 28,000 miles; 69% of problems with a recorded mileage started before 50,000 miles.
Source: U.S. National Highway Traffic Safety Administration (NHTSA) — owner complaints through October 20, 2026, recalls and defect investigations; fuel economy from the EPA. Complaints are unverified reports and are not proof of a defect. How we rate model years.