GMC · Known Issues
2018 GMC Terrain Problems: 8 Known Issues
2018 model year · 740+ owner reports · Updated September 2026
2018 · All trims · All engines
Choose the year and equipment for your written issues and visual request.
2018 model year · 740+ owner reports · Updated September 2026
2018 · All trims · All engines
Choose the year and equipment for your written issues and visual request.
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According to Au7o's analysis of 740+ owner reports, the 2018 GMC Terrain has 8 documented known issues, with 4 rated critical. The most serious are 1.5L Turbo PCV System Failure and Coolant/Oil Intrusion ($400-$2,800 repair), Start/Stop Transmission Accumulator Endcap Missing Bolts - Fluid Leak & Loss of Propulsion (Recall), Engine-Driven Brake Vacuum Pump Failure - Sudden Loss of Power Brake Assist (Hard Pedal) ($400-$1,500 repair) and Charge Air Cooler Outlet Duct Disconnecting at the Throttle Body - Sudden Power Loss and Stall ($0-$250 repair). The most commonly reported issue is 1.5L Turbo PCV System Failure and Coolant/Oil Intrusion with 740 owner reports. Across all issues with published estimates, repair costs range from $100 to $2,800. DIY maintenance guides at au7o.io.
AIR BAGS:SENSOR:OCCUPANT CLASSIFICATION:FRONT PASSENGER
General Motors, LLC (GM) is recalling certain 2023 Chevrolet Equinox and GMC Terrain vehicles equipped with ventilated front passenger seats. The Occupant Classification System may not properly disable the front passenger air bag when there is a small child or child restraint detected in the seat.
CHILD SEAT:VEHICLE LATCH ANCHOR
General Motors, LLC (GM) is recalling certain 2020-2023 Chevrolet Equinox and GMC Terrain vehicles. The four rear-seat lower child seat LATCH anchorage bars may have excessive powder coating, which could prevent a child seat from being installed with the anchorage bars. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard number 225, "Child Restraint Anchorage Systems."
STRUCTURE:BODY:DOOR
General Motors, LLC (GM) is recalling certain 2024 Chevrolet Blazer, Blazer EV, Equinox, and GMC Terrain vehicles. The door strikers may fracture, resulting in the door opening unexpectedly.
SEATS
General Motors, LLC (GM) is recalling certain 2022-2023 Chevrolet Equinox and 2022 GMC Terrain vehicles. The driver's seat may have a stripped or loose bolt at the seat frame height-adjust pivot.
TIRES
General Motors, LLC (GM) is recalling certain 2021-2022 Chevrolet Equinox and GMC Terrain vehicles equipped with certain Hankook tires. The tires may have been manufactured with an insufficient amount of curative agent, which could cause tread separation.
Enter your VIN at NHTSA.gov to check recalls specific to your vehicle.
Don't see your problem? Describe your symptoms to get a diagnosis, or get a full repair guide.
According to Au7o's analysis of 740+ owner reports, the 2018 GMC Terrain has 8 documented issues. The most frequently reported are: 1.5L Turbo PCV System Failure and Coolant/Oil Intrusion, Start/Stop Transmission Accumulator Endcap Missing Bolts - Fluid Leak & Loss of Propulsion (Recall), Engine-Driven Brake Vacuum Pump Failure - Sudden Loss of Power Brake Assist (Hard Pedal). Of these, 4 are rated critical and should be addressed promptly.
The 2018 GMC Terrain has 8 known issues documented across 740+ owner reports. 4 issues are rated critical: 1.5L Turbo PCV System Failure and Coolant/Oil Intrusion and Start/Stop Transmission Accumulator Endcap Missing Bolts - Fluid Leak & Loss of Propulsion (Recall) and Engine-Driven Brake Vacuum Pump Failure - Sudden Loss of Power Brake Assist (Hard Pedal) and Charge Air Cooler Outlet Duct Disconnecting at the Throttle Body - Sudden Power Loss and Stall. Prospective buyers should inspect for these issues and factor potential repair costs into their purchase decision. Regular maintenance following the manufacturer's schedule helps prevent many common problems.
Repair costs for known GMC Terrain issues range from $0 to $2,800, depending on the specific problem and whether you choose DIY or professional repair. The most critical issue, 1.5L Turbo PCV System Failure and Coolant/Oil Intrusion, typically costs $400-$2,800 to repair. Au7o provides step-by-step DIY maintenance guides that can help reduce repair costs.
The 2018+ Terrain with the 1.5L turbocharged engine (LFV/LYX) experiences PCV (Positive Crankcase Ventilation) diaphragm failure inside the valve cover. The integrated PCV diaphragm tears, causing excessive crankcase pressure that forces oil into the intake manifold and intercool… Repairs typically run $400-$2,800. Severity: high.
NHTSA campaign 20V668 covers certain 2018-2020 GMC Terrain vehicles. Missing bolts on the transmission start/stop accumulator endcap can cause a transmission-fluid leak, loss of propulsion and possible fire. Severity: high.
On second-generation Terrains (2018-2022) with the 1.5L LYX and 2.0L LTG turbo engines, the camshaft-driven mechanical vacuum pump that supplies the brake booster can fail suddenly and without warning. When it fails, drivers lose power brake assist and the pedal becomes hard as a… Repairs typically run $400-$1,500. Severity: high.
On 1.5L LYX-equipped Terrains the charge air cooler outlet tube can separate from the throttle body inlet. The retaining clip design does not hold the duct under boost pressure and heat cycling, so the tube pops off, dumping boost and unmetered air. GM issued Service Update N1922… Repairs typically run $0-$250. Severity: high.
Terrain front and rear hub assemblies integrate the ABS magnetic encoder ring into the bearing's inboard seal, where it sits directly exposed to road salt and moisture. Two distinct failure modes result. The mechanical one is the familiar humming or roaring that rises with speed… Repairs typically run $300-$800. Severity: medium.
Second-generation Terrains with the electronic precision (push-button/monostable) shifter throw a persistent "Shift to Park" warning and refuse to shift out of (or fully into) park even when correctly positioned. GM traced it to build-up/contamination on the Park switch contacts… Repairs typically run $150-$1,500. Severity: medium.
On the second-generation Terrain (2018+) with the turbocharged 1.5L LYX or 2.0L LTG engine, the air-to-air charge air cooler (intercooler) accumulates condensate from humid or rainy driving plus PCV-borne moisture. In cold ambient temperatures that water freezes inside the CAC co… Repairs typically run $150-$900. Severity: medium.
The IntelliLink/MyLink touchscreen freezes and spontaneously reboots, losing control of radio, climate, navigation and Bluetooth, and often displays a black screen or a frozen backup-camera image. During a reboot, phone calls drop and the rear camera can go dark while in reverse… Repairs typically run $100-$900. Severity: low.
Content on this page was compiled with AI assistance using NHTSA complaints, TSBs, owner reports, and public automotive data. While we strive for accuracy, this information may contain errors. Always verify repair procedures and specifications with your vehicle's service manual or a qualified mechanic.