2004 Mercury Mountaineer Repair and Maintenance
A guide to problems, costs, maintenance and repair for your 2004 Mercury Mountaineer
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2004 Mercury Mountaineer ProblemsPlastic Intake Manifold May Crack Causing Coolant Leak
The composite (plastic) intake manifold may crack near the thermostat housing and cause a coolant leak. Ford released an updated manifold that was reinforced to prevent a recurrence. No recall was issued for this problem but Ford did extend the warranty to seven years on some models from the date of purchase.
Various problems with the 5-speed automatic transmission were common. These problems can be more common on the 2002 models with build dates before March, 2002. There are many service bulletins describing the diagnoses and repairs, which include fluid leak repairs, transmission software updates, or internal failures requiring a costly repair.
A failed heater blend door or actuator can cause the temperature control for the HVAC system to stop working. A clicking sound from the dash area would commonly indicate an actuator fault. If the heater gets stuck on the hottest setting, the heater blend door may be broken requiring replacement of the heater box to repair the issue.