Cooling System Servicing: Maintenance: Flushing

CAUTION: Aluminum and plastic materials are used in radiators. Flushing solution used must be compatible with aluminum.

Back flushing is an effective means of removing cooling system rust and scale. The radiator, engine and heater must be flushed separately. In severe cases, the pressure flushing method may be used. Always remove thermostat prior to pressure flushing. Do not back flush systems that have water shut-off valve in heater system, damage to valve can result. Various types of flushing equipment are available. Follow manufacturer's directions carefully.
To flush radiator, connect flushing gun to water outlet of radiator and disconnect water inlet hose. To prevent flooding engine, attach a hose to radiator inlet. Use air in short bursts to prevent damage to radiator. Continue flushing until water runs clear.
To flush engine, remove thermostat and replace housing. Connect flushing gun to water outlet of engine. Flush system while using short air bursts until water runs clean. Flush heater core as described for radiator. Ensure heater control valve is set to maximum heat position before flushing heater.