One problem related to engine cooling system has been reported for the 1998 Mercury Grand Marquis. The most recently reported issues are listed below.
The plastic intake manifold in my 1998 Grand Marquis has cracked resulting in engine coolant fluid leak and engine failure. It is being repaired today. The car has approximately 87,000 miles. I understand that this occurs because of the material used for the intake manifold. The car is in otherwise very good condition.