Ranger 4WD V6-3.0L VIN U (1997)
Heater Core: Service and Repair
Back Flushing-Heater Core
All engine cooling system flushing and back-flushing procedures must include a separate back-flushing of the heater or air conditioning system heater
core, after the flushing or back-flushing of the engine cooling system.
The correct back-flushing procedure for heater core is as follows:
1. Disconnect the heater core outlet hose from the water pump fitting and install a female garden hose-end fitting adapter in the end of the outlet
heater hose. Secure with a hose clamp.
2. Connect the female garden hose end of the outlet heater hose to the male end of a water supply garden hose.
3. Disconnect the heater core inlet hose from the engine block fitting and allow to drain into an appropriate container.
4. Check to be certain the water valve is open (no vacuum) if a water valve is installed in the heater core inlet hose.
5. Turn the water supply valve on and off several times so that the surge action helps to dislodge larger stubborn particles from the heater core tubes.
Allow full water pressure to flow for approximately five minutes.
6. Apply vacuum to the water valve vacuum motor, if a water valve is installed in the heater core inlet heater hose, to ensure proper operation of the
water valve and proper closure with no water leakage. Replace the water valve if required.
7. Remove the hose clamp and female garden hose end adapter from the end of the outlet heater hose and reconnect the outlet heater hose onto the
water pump fitting.
8. Connect the inlet heater hose onto the engine block fitting.
9. Fill the cooling system.
10. Test the system for proper heater performance with the specified engine cooling system conditions.
