Ranger 4WD V6-3.0L VIN U (1997)
Heater Core: Testing and Inspection
In Vehicle
PRESSURE TEST
1. Drain the coolant from the cooling system.
2. Disconnect the heater water hoses from the heater core.
3. Install a short piece of heater water hose (approximately 101.6 mm [4 inches] long) on each 19.05 mm (3/4-inch) heater core coupling. Connect
couplings to heater core.
4. Fill the heater core and heater water hoses with water and install Plug BT-7422-B and Adapter BT-7422-A from Rotunda Radiator/Heater Core
Pressure Tester or equivalent in the ends. Secure the heater water hoses, plug, and adapter with hose clamps.
5. Attach the Rotunda Radiator/Heater Core Pressure Tester or equivalent to the adapter. Close the bleed valve at the base of the gauge and pump
206 kPa (30 psi) of air pressure into the heater core.
6. Observe the pressure gauge for a minimum of three minutes. The pressure should not drop.
7. If the pressure does not drop, no leaks are indicated.
8. If the pressure drops, check the coupling or hose connections to the core tubes for leaks. If the couplings or heater water hoses do not leak, remove
the heater core from the vehicle and bench test the heater core.
NOTE: Severe distortion of the core tubes could cause leakage at the coupling connection; repair or replace as necessary.
