bIG JOB Get a manual on your car from DISCOUNTAUTOREPAIRMANUALS.COM and see if you want to go to that much trouble.
change out the heater core
Instualation of a heater core on a 1999 Ford Explorer V6, how do you install the heater core.
See previous question of same nature.
This is an indication that your heater core is leaking. To stop the leaking you will have to replace the heater core or stop using your heater.
How do i change the heater core on a 1997 ford e150
heater core is in back of the glove box
To change the heater core in a 87 ford f150 is easy. Just remove the glove box and then behind it there is 7 bolts. After you remove the 7 bolts then just remove the cover and behind it is the heater core. By far the easiest heater core I ever changed.
The heater core will have to be replace, it is not hard to do and the Heater Core is about $35 at the auto parts store. Good Luck
Remove the glove box and you'll have access to the heater core, still not easy.
The Heater Core will be located behind the dash. Hope that Helps.
Doesn't matter which way the water flows. The heater core is just a tube with fins and water can flow either direction.
Look near or behind the alternator. The valve that controls flow of coolant to the heater core on my 1987 Aerostar is located on the left wall of the engine compartment. I imagine the 1991 is similar. Trace the heater hoses from the engine/water pump and you will find it.