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.Google+
Car Problem Reports
Mercury Grand Marquis Engine May Overheat at Idle With AC On
Mercury Grand Marquis Problem
Average Mileage: 67,154 mi (23,000 mi - 110,000 mi)
Visitor, 2007 Mercury Grand Marquis, 110,000 mi
Replace engine cooling fan
Visitor, 2008 Mercury Grand Marquis, 55,000 mi
The engine may overheat at idle when the AC is on. A new, upgraded fan motor and resistor assembly should be put in.
MY 2004 Mercury Grand Marque over heated in June while I was waiting on a red light to change, dumping all fluid and stranding me.
I waited 2-weeks for my son to check out the car and he changed the thermostat and I drove it to the doctor next day and it over heated again. We added more antifreeze and I have not had that problem since, just a new host of problems. The A/C will only flow hot air, the passenger window if, I put it down it can only be put back up by force, the door can not be locked with the remote, I purchased a inside window washer and the long handle makes it easy to lock the door. My headlights went out and I also received the recall letter in April about that problem, the headlight problem did not occur till early on a very dark November morning when I was on my way to take my sister, for surgery, to the hospital.
My car is now at the dealership for all electrical problems to be fixed and I understand the headlight part my not be available for months. Happy days are ahead.
Blowing hot air when idling or car was stationary. Drove it 15-20 miles....turned car off...started it up right away and the car made a strange sound and dumped contents of radiator....overheated. Dealership replaced fan and module $1000.