Two problems related to power train have been reported for the 1999 Mercury Grand Marquis. The most recently reported issues are listed below.
Plastic intake manifold on 4. 6 liter engine found to be cracked and leaking coolant. The loss of coolant results in the vehicle becoming disabled and/or unsafe to drive. Leaking coolant is also toxic to children and animals, as they are more likely to be in contact with coolant on the ground or garage floor. This defective part (plastic intake manifold) was identified by Ford motor company as defective and quietly settled in a class action lawsuit. Replacement parts have been redesigned. However, Ford did not contact customers with this model car to notify them of the defective part or to offer resolution. Earlier models of this engine (and all other engines) used a metal intake manifold. These were not problematic. Intake manifolds are not a moving part of the vehicle engine, and are not subject to ware. The plastic material used in the problem manifolds are not able to withstand the normal temperature fluctuations of a vehicle engine and are therefore prone to failure. Ford has been contacted in an attempt to resolve this issue, but the company has declined to offer any resolution whatsoever.
The contact owns a 1999 Mercury Grand Marquis. The contact stated that the vehicle started stalling with the illumination of the check engine warning light. The vehicle was taken to the dealer. The dealer advised that the transmission would need replacing. The vehicle was repaired. The manufacturer was contacted and stated that the vehicle was not under recall. The failure mileage was 120,000 and the current mileage was 126,000.