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Home >> Ford >> 1998 >> Crown Victoria V8-281 4.6L SFI >> Repair and Diagnosis >> Heating and Air Conditioning >> Heater Core >> Service and Repair >> Back Flushing-Heater Core
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Back Flushing-Heater Core

CAUTION: The heater core must be back-flushed separately from the engine cooling system for proper back-flush water flow through the heater core.

All engine cooling system flushing and back-flushing procedures must include a separate back-flushing of the heater core after the flushing or back-flushing of the engine cooling system This will prevent engine cooling system particles from clogging the heater core tubes and reducing (or eliminating) coolant flow through the heater core.

The correct heater core back-flushing procedure is as follows:
1. Disconnect the heater core outlet heater water hose from the return fitting and install a female garden hose-end fitting adapter in the end of the outlet heater water hose. Secure with a hose clamp.
2. Connect the female end of the outlet heater water hose to the male end of a water supply garden hose.
3. Disconnect the heater core inlet heater water hose from the intake manifold fitting. Allow to drain into a suitable container.
4. If a water valve is installed in the heater core inlet heater water hose, check to be certain the water valve is open (no vacuum).
5. Turn the water supply valve on and off several times so that the surge action will help to dislodge larger stubborn particles from the heater core tubes. Allow full water pressure to flow for approximately five minutes.
6. If a water valve is installed in the heater core inlet heater water hose, apply vacuum to the water valve vacuum motor to make sure 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 water hose and reconnect the outlet heater water hose onto the water pump fitting and heater return fitting.
8. Connect the inlet heater water hose onto the cylinder block fitting and intake manifold fitting.
9. Fill the engine cooling system, using a 50/50 mixture of Ford Premium Cooling System Fluid E2FZ-19549-AA (green), Ford Extended Life Engine Coolant F6AZ-19544-AA (orange), or equivalent and water.
10. Test the system for proper heater performance with the specified engine cooling system conditions.

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