Damage to the heater core on the Aerostar most often happens from sediment buildups that cause it to clog and then rupture. A typical sign of a damaged heater core is coolant on the floor area. However, one of the first signs you may notice is a greasy film on the glass at the base of the windshield. You can change the heater core on the 1991 Ford Aerostar right at home. It mounts against the firewall on the passenger side and with a few tools the repair should take 35 minutes to do.
Instructions
1. Lift the hood on your Aerostar and remove the radiator cap. If you've just driven the van, wait 30 minutes to one full hour before you remove the cap. This way, the pressure inside of the entire cooling system will have died down and won't spew hot coolant all over you.
2. Position a coolant drain pan beneath the radiator and then carefully open the drain plug. Allow half of the coolant to drain, and then close the drain plug securely. Don't remove the drain plug completely--that's not necessary. Just open it enough to allow a steady flow of coolant to come out.
3. Remove the heater core hoses one at a time where they connect at the back of the firewall using the hose disconnect tool. After you disconnect the first hose, quickly insert a heater hose plug to prevent possible coolant leakage. Plug the second hose when you remove it as well.
4. Open the passenger-side door and kneel down so you're able to see the heater core's case cover beneath the dashboard. The cover looks like a short, black rectangle with grooves in it.
5. Remove the six screws holding the cover in position with a Phillips screwdriver and then take the cover off. Place the cover to the side and put the screws in your pocket.
6. Place three large shop towels on the floor area directly beneath the heater core. You may want to keep each of the towels folded instead of just spreading them out. The heater core still has a lot of coolant in it and nearly 100 percent of the time some of it spills during removal.
7. Remove the heater core by depressing the retaining bracket at the top of it while pulling the bottom of the heater core toward you. Carefully lower the heater core from its housing and then drain the coolant out of it into the coolant drain pan.
8. Install the new heater core by reversing the removal steps. Both heater core hoses simply push back onto the inlet and outlet tubes on the heater core. Fill your radiator with the drain pan's coolant or completely drain the rest of the coolant in the radiator and refill it with fresh coolant.
Tags: heater core, coolant drain, drain plug, 1991 Ford, 1991 Ford Aerostar, core hoses, drain coolant
