Reverse Flushing Engine
Drain the cooling system. Remove the thermostat housing and remove the thermostat from the housing. Install the thermostat housing. Disconnect the upper radiator hose from the radiator and attach the flushing gun to the hose. Disconnect the lower radiator hose from the water pump and attach a lead away hose to the water pump inlet fitting.
On vehicles equipped with a heater water control valve, be sure heater control valve is closed (heat off). This will prevent coolant flow with scale and other deposits from entering heater core.
Connect the water and air supply hoses to the flushing gun. Allow the engine to fill with water. When the engine is filled, gently apply air in short blasts, allowing the system to fill between air blasts. Continue until clean water flows through the lead away hose.
Remove the lead away hose, flushing gun, water supply hose and air supply hose. Remove the thermostat housing and install the thermostat using a NEW gasket. Refer to THERMOSTAT, INSTALLATION . Connect the radiator hoses. Fill the cooling system with the correct antifreeze/water mixture. Refer to STANDARD PROCEDURE .