2018 GMC Sierra engine problems
78 of the 321 complaints owners filed with NHTSA about the 2018 GMC Sierra name the engine (NHTSA’s “Engine” heading — the engine and its cooling system). Filed under the same heading: 546 manufacturer bulletins. Every figure below is a document in a federal file, linked; none is a failure rate, and none is a verdict on any one car.
What owners filed about the engine
Source: NHTSA complaint database0 of the 78 reports a crash · 0 a fire · 0 injuries. Self-reported, unverified.
Filed per year: 2018: 1 · 2019: 3 · 2020: 7 · 2021: 6 · 2022: 4 · 2023: 7 · 2024: 6 · 2025: 31 · 2026: 13
Half of the 26 owners who gave an odometer reading reported the engine problem between 36,000 and 107,000 miles. A median of reports, not the life of a part.
321 complaints in all about the 2018 GMC Sierra, 13 filed in 2026. The whole picture, every system →
Counts are owner reports to NHTSA, not verified defects, and scale with how many of these were sold; nothing here is a rate. NHTSA groups complaints coarsely, so “Engine” means the same area of the vehicle, not one fault.
Across model years: GMC Sierra engine problems, every year on file →
In owners’ own words
Source: NHTSA complaint databaseFiled with NHTSA by the people who own these cars, about the engine. Quoted as written, with anything identifying removed; unverified reports — what was said, not a finding that it was true.
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.
While driving with the roads in a wet condition, for various lengths of time, and in different maneuvers, the service engine light will start flashing and the vehicle will begin to lose power. After a few minutes, the service engine light will go solid and the traction control light will illuminate. The vehicle loses more power.
The contact owns a 2018 Gmc Sierra 1500. The contact stated that a coolant smell would emit from the vehicle upon exit. The contact also stated that his vehicle had began to lose coolant at an abnormal rate and had to be frequently replaced.
The radiator is leaking coolant without any real cause and I was told the entire radiator needs to be replaced
Driving down the highway about 65mph it made a loud clunk and I took it in to service department and they told me I would have to pay about $400.00 to drain the transmission fluid and replace it.
What is on file about the engine
Source: NHTSA recalls, investigations and manufacturer communications546 manufacturer bulletins filed under this heading
The 0 newest are listed; every one is on the model year’s page. Quote the document number at a service desk — it is a diagnosis the maker has already written down.
Trouble codes named on this system
P0300 B3055 B3060 B3935 P0308 P050D P2463 P140B
Codes a bulletin or an owner’s complaint about the 2018 GMC Sierra names on this model year; a code with a record of its own links it.
Other systems with a record on the 2018 GMC Sierra
Source: the same files- transmission and drivetrain problems 133 complaints
Common questions
Source: NHTSA complaint database, recalls and manufacturer communicationsAre engine problems common on the 2018 GMC Sierra?
They are documented: NHTSA holds 78 owner complaints naming the engine on this model year (24% of everything owners filed about it), and 546 manufacturer bulletins are filed under the same heading. Whether it is a problem on one particular car is a diagnosis, not a count, and a count says nothing about how many were sold.
Is there a recall for the engine on the 2018 GMC Sierra?
No recall campaign is filed under this heading for this model year (there are 7 filed under other headings). A bulletin is not a recall: it carries no federal duty to repair for free.
When do engine problems show up on the 2018 GMC Sierra?
Owners who gave an odometer reading reported it at a median of 59,000 miles; half of them between 36,000 and 107,000. That is when reports cluster, not the life of a part.
What does NHTSA's "Engine" heading cover?
The engine and its cooling system. Owners choose the heading when they file, so it says which area of the vehicle the complaint is about, not which part failed.