2018 GMC Acadia: What to check before buying

The car fails to recognize Park, the most common complaint by far. A "Shift to Park" message and chime stay on, the car won't shut off or lock, and the battery drains. Several reports say the car rolled after the driver left it, including a garage crash. Onset clusters between about 12,000 and 48,000 miles. Shifter repairs often don't hold, and one dealer had no parts. Less often, the transmission slips on the warm 2-3 upshift or the car stalls on the highway. One report describes a fractured front half shaft.

"Shift to Park" faults lead this category too. One dealer found a shifter switch that wasn't grounding, and some owners paid for shifter, harness and module replacements at low mileage. Other reports describe the engine shutting off or losing power on highways, random no-starts, dead batteries, and dash lights going dark while driving. Another pattern is a powertrain computer fault that knocks out the temperature gauge, power steering assist and air conditioning together. One car caught fire while idling in a driveway, and one crash is linked to engine shutdowns.

A "Steering Assist Reduced, Drive with Care" warning appears without notice, and the wheel turns heavy and stiff. Along with it, the coolant gauge drops to zero or flatlines, the air conditioning cuts out and the cooling fan runs loud. Shops read code P0128 and replace the thermostat and coolant temperature sensor, but some owners say the warning comes back. Two crashes with five injuries appear here: one loss of control on a curve and one where the car sped up and the brakes didn't stop it.

The electric parking brake locks up on its own or won't release, and in some cases owners are stranded or need a tow. One lockup burned out the actuator. Other reports describe a StabiliTrak fault that set off the ABS at highway speed, fixed with a wheel sensor and brake control module, and a rear pad separating from its backing plate. Of two crashes, one involved sudden acceleration with brakes that didn't stop the car and four injuries. The other was a rollaway after a "Shift to Park" fault, which several other reports also describe.

The thermostat or its housing fails, often sticking open, and that sets off a reduced steering assist warning, shuts off the air conditioning and runs the fan hard. One owner had the housing replaced twice in 3 years and was told emissions coverage includes the thermostat but not the housing. One report covers a torque converter failure that led to a transmission replacement, with hard shifting and no-starts. The rest describe the "Shift to Park" fault, which keeps the car from shutting off and drains the battery.

Rear suspension links wear or break. One rear lower control arm snapped in half at parking-lot speed and turned the wheel sharply. Rust at the break suggested the crack had been spreading for a while. Another car failed state inspection with worn rear control arm bushings that moved by hand at 41,633 miles, and the shop called this common. Toe links broke while driving in a third case, and the driver nearly lost control.

None of these reports actually describe a stability control fault. All four describe the car not recognizing Park. The "Shift to Park" message stays up, the car stays in accessory mode with the dash lit, and the doors won't lock. Drivers restart and run through the gears many times to clear it, in one case for an hour. Left alone, the fault drains the battery, and owners worry the car could move on its own. It comes and goes at first, then gets worse.

Tires wear out early. One set was worn out at 23,700 miles. On another car, the front tread tore and gouged even with regular rotation and no accident or off-road use. One complaint filed here is really a body leak: water came in through the rear windows, door panels and headliner after rain on a car with 8,000 miles.