To flush just the radiator, you remove the upper and lower radiator hoses from the thermostat housing and water pump inlet. (Leave the hoses in place on the radiator) Place a water hose inside of the upper radiator hose, direct the lower radiator hose into a bucket, and turn the water on. Flush until the water flows clear.
However, it doesn't make much sense to flush only the radiator. If the radiator is clogged up with debre's, then the rest of the system will surely have the same dibres.
To flush the entire system:
Remove your thermostat housing and thermostat. Then replace the housing without the thermostat. Turn the engine on and place your heater controls on full hot. Remove the upper radiator hose from the radiator, leaving the hose connected to the thermostat housing (Leave the bottom hose intact), place the water hose inside of the hose and flush until the water is clear.
When you're done, run the motor until the water pump has pushed out all of the plain water. Then cut the motor off and refill with coolant.
Friday, January 8th, 2010 AT 2:09 PM