That is one of hundreds of possibilities.
See related questions below.
Check the engine end of the upper radiator hose
The thermostat is located on the front of the engine under the elbow at the end of the radiator hose
Could be the rad. , the thermostat, hoses, fan. You have to check all.
On a 1999 Mercury Grand Marquis , 4.6 liter V8 engine : The Original Equipment engine cooling thermostat would be : ( around 192 * Fahrenheit )
Check to insure that the engine coolant is full and the thermostat is not stuck. Without the heated fluid from the engine the heater will always blow cold air.
Yes
On a 1999 Mercury Grand Marquis : The Original Equipment engine cooling thermostat would have been ( around 192 * Fahrenheit )
A crack near or on the thermostat housing can cause a coolant leak in a 1996 Grand Marquis. The thermostat housing is located near the manifold on this vehicle.
The engine in a 1993 grand marquis is a 4.6 litre/281 cubic inch.
Have vehicle scanned to determine the problem
how to replace starter on 2000 mercury grand marquis
Replacing the thermostat on a 1996 Grand Marquis is not very hard. First, follow the upper radiator hose to find the thermostat. Then disconnect the hose and drain it. After the hose is drained, remove the bolts holing the thermostat housing in place. Take the old thermostat out and replace with a new one.