Heater Core
- Check for proper coolant level. Start engine and turn heater on. When engine reaches normal operating temperature, feel heater outlet hose. It should be hot. If outlet hose is not hot, heater core may have an air pocket, heater core may be plugged, or thermostat may not be working properly.
- Drain cooling system. Disconnect heater hoses from heater core. Install a short piece of heater hose, about 4" (101 mm) long on each heater core tube.
- Fill heater core and heater hoses with water. Install Plug (BT-7422-B) on one end of hose and Adapter (BT-7422-A) on other hose end. Secure hoses, plug, and adapter with hose clamps. See Fig 1
.
- Attach pump and gauge assembly from a radiator/pressure tester to adapter. Close tester bleed valve and apply 35 psi (2.46 kg/cm2
) air pressure to heater core. Observe gauge for 3 minutes.
- If pressure drops, check all hose clamp connections for proper fit; replace leaking hoses or clamps. If hoses do not leak, replace heater core.
Courtesy of FORD MOTOR CO.