2018 GMC Terrain Reliability Score & Common Problems

Owners of the 2018 GMC Terrain frequently report transmission issues, including locking up, inability to shift, and sudden shifts to park while driving, often occurring around 70,000 miles. Multiple complaints also describe problems with the auto-stop feature, which lacks a disable option and can lead to unexpected vehicle rollbacks on inclines. Additionally, several owners mention infotainment system malfunctions, including blackouts and burning smells, as well as rear camera haziness and moonroof explosions, both posing visibility and safety risks. These issues are often associated with significant safety implications, such as potential loss of control and increased accident risk.

Owners of the 2018 GMC Terrain frequently report engine issues, with many citing sudden stalling or the vehicle entering "limp mode" without warning lights or prior indications. Common symptoms include the vehicle slowing down unexpectedly, displaying "Engine Power Reduced" messages, and failing to restart. These issues often occur at varying mileages, with some reports around 30,000 to 121,000 miles. Safety implications are significant, as several complaints describe the car stalling in traffic or on highways, posing risks of collisions. Additionally, multiple owners note problems with the vacuum pump and catalytic converter failures, leading to further engine complications.

Owners of the 2018 GMC Terrain frequently report issues with the airbag system, particularly the failure of airbags to deploy during crashes. Complaints often mention warning lights for the "Service Safety Restraint System" and the airbag indicator illuminating on the dashboard. These issues are reported both shortly after purchase and at mileage around 55,705. Safety implications are significant, as six out of the eleven complaints involve crashes, with seven injuries reported. Prospective buyers should be aware of these recurring airbag system malfunctions and consider the potential for non-deployment in crash scenarios.

Owners of the 2018 GMC Terrain report several steering-related issues, including sudden loss of control and power steering malfunctions. Complaints frequently mention unexpected veering, difficulty in steering, and the steering wheel not returning to the center position. Two incidents involve crashes, with one describing a vehicle veering uncontrollably, resulting in a severe accident, and another involving a loss of control during a turn. Some owners note problems with warning lights and steering assist failures, often occurring after braking or during specific maneuvers. These issues are reported at various mileage points, with one vehicle having been purchased used at 50,000 miles. Safety implications are significant, as these problems can lead to crashes and potential injuries.

Owners of the 2018 GMC Terrain report issues related to the fuel and propulsion system, primarily involving fuel leaks and turbo boost failures. Complaints frequently mention fuel leaks from the tank and diesel fuel lines, with visible gasoline puddles and diesel leaks occurring when the vehicle is both parked and in gear. Turbo boost failures are associated with significant power loss, sluggish acceleration, and poor fuel economy, often accompanied by blue smoke and unusual engine noises. Some owners express safety concerns due to these issues, particularly the potential for engine damage from turbo failures and the risk of fire from fuel leaks. These complaints do not specify mileage, but they highlight potential safety risks that prospective buyers should consider.

Owners of the 2018 GMC Terrain report issues related to visibility, specifically involving the headliner fabric and the rearview camera display. One complaint describes the headliner fabric detaching from the panoramic track, obstructing the rear and back window view, creating a safety hazard while driving. Another common issue involves the rearview camera display, which remains excessively bright at night, reflecting off the windows and impairing visibility when reversing. This problem is noted as permanent and repeatable, with one owner reporting it as early as 300 miles. These visibility issues are noted as safety concerns, particularly in low-light conditions, and may impact safe maneuvering of the vehicle.

Owners report issues with the seats of the 2018 GMC Terrain, highlighting problems with both seat adjustability and structural integrity. Multiple complaints describe the driver seat's inability to raise or incline, impacting visibility while driving. Additionally, a front passenger seat issue is noted where a bolt snaps, causing the seat to become unstable and rock back and forth. Another complaint mentions a manual lever for height adjustment that repeatedly comes off track, requiring dealership intervention. These issues occur without specific mileage data, but the instability of the passenger seat may have safety implications if not addressed.