Common problems with a Mercury Mountaineer include cracks on the lift gate, transmission issues, cracking of the plastic intake manifold and a faulty rear panel. Other problems include engine surges, sticking of the heater on the hottest setting and failure of the rear window wiper to contact the rear window.
Cracks on the lift gate of the Mercury Mountaineer may be caused by a defective lift gate trim panel. The cosmetic crack on the plastic panel may lead to damage of the lift gate glass. Transmission problems are caused by poor maintenance, faulty solenoids, and failure to change the transmission oil and filter. These problems lead to noises and delays in transmission.
The composite intake manifold next to the thermostat may crack leading to coolant leaks in the Mercury Mountaineer. Preventing this problem requires reinforcement of the plastic composite manifold. Rear panel defects are caused by pressure originating from buildup of water on the window panel. This develops into cracks on the rear panel.
Engine surges result from a binding situation caused by faulty clearance of the bore and the throttle plate. When the actuator or heater blend door fails, the temperature control in the Mercury Mountaineer stops working properly. This leads to clicking sounds near the dash area indicating a faulty actuator. Additionally, when the heater blend door is broken, it leads to sticking of the heater when it's on the hottest setting.