What reliability score does the GMC Terrain get?

5.7 out of 10, scored from the 8 faults we document for this model and how severe each one is.

Is the 2018–2023 GMC Terrain reliable?

Scored from 8 documented faults · reviewed by the VehicleFaults Research Team

Quick answer

5.7/ 10

Mixed

On our documented-fault scoring the GMC Terrain rates 5.7 out of 10 · mixed. We hold 8 known faults for it and 1 are rated high severity, so the risk is real but contained. The weak points cluster around electrical, engine and transmission. A well-serviced example with evidence for the big-ticket items is usually a safe buy; the score describes the model, not the specific car in front of you.

Verdict · Negotiate · budget for the known faults

What the score is built from

Critical: 0
High: 1
Medium: 5
Low: 2

Weak points cluster around electrical, engine, transmission, hvac.

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The faults that decide it

BrakesHigh

Hard brake pedal and reduced braking assistance due to mechanical vacuum pump failure on 1.5T models.

Typically appears: 40,000-70,000 miles
What to inspect: Start the engine and pump the brake pedal rapidly three to four times. If the pedal becomes rock hard and fails to regain vacuum assistance within a few seconds, the pump is failing.
Typical repair: Brakes (discs, pads, caliper) · £200–£800

EngineMedium

1.5T carbon build-up / oil consumption.

Typically appears: 60,000+ miles
What to inspect: Check oil level and watch for rough idle.
Typical repair: Oil leak trace & seal / gasket · £180–£700

TransmissionMedium

9-speed shudder and shift-to-park glitch.

Typically appears: Any
What to inspect: Feel for shudder and confirm clean park engagement.
Typical repair: Routine repair · £180–£700

HVACMedium

AC condenser faults.

Typically appears: 70,000+ miles
What to inspect: Confirm cold AC output.
Typical repair: Routine repair · £180–£700

BodyworkMedium

Water ingress into the cabin caused by blocked or detached panoramic sunroof drain tubes.

Typically appears: 3-5 years
What to inspect: Press firmly into the front footwell carpets to feel for dampness. Open the sunroof and check the front corner drain channels for standing water, silt, or leaf debris.
Typical repair: Body & corrosion repair · £250–£1,800

Costs are indicative UK independent-garage bands for budgeting and negotiation · never a quote.

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What the score is built from

The faults that decide it

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