Heater Control Valve: Service and Repair

Removal
1. Remove pressure cap, being sure to relieve pressure if system is warm.
2. Disconnect vacuum line at top of heater valve body to allow valve to open fully, venting heater core for drainage.
3. Partially drain cooling system by opening drain valve in radiator fill tube or right end tank. Drain until pinching the bypass line return hose at the water pump inlet indicates coolant has dropped below this level, then close drain valve.
4. Disconnect inlet hose, oil cooler outlet hose and the heater core connecting hoses from the heater valve.
5. Twist heater valve body out of mounting clip.

Installation
1. Snap heater valve into spring mounting clip with upper and lower hoses nipples aligned with heater core connecting hoses, then connect hoses, torquing hoses clamps to 21-31 inch lbs.
2. Connect oil inlet hose to center hose nipple between heater core connections, and the oil cooler outlet hose to the remaining hose nipple, torquing hose clamps to 21-31 inch lbs.
3. Connect vacuum hose to fitting on top of heater valve.
4. Fill system with coolant, install pressure cap and warm up engine to pressurize system, then check for leaks.