1998 Mercury Grand Marquis Problems
RepairPal has identified the most common problems with the 1998 Mercury Grand Marquis based on complaints from actual vehicle owners. We'll tell you what the problem is and what it'll take to fix it.
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.
If you experience difficulty starting the engine when cold, stalling at idle, or hesitations during acceleration, it may be the idle air bypass valve. This valve helps the vehicle idle steady when the accelerator pedal is not pressed.
Transmission problems are common in this model, often as a result of a failed front pump. The pump loses its ability to create hydraulic pressure, which an automatic transmission needs to function. A sign of front pump failure can be a whine type noise.
A spring in the seat belt buckle may wear or fail, causing the airbag light on the instrument panel to illuminate. Failed buckles will require replacement.
The engine may overheat at idle when the AC is on. A new, upgraded fan motor and resistor may be required to correct this concern.
The alternator may get too hot, causing premature bearing failure.