Join Date: Sep 2000
Location: Washington, Michigan USA
When re-filling your cooling system (after draining it down to change an intake or water pump), fill it up to the top of the opening in the intake for the thermostat housing first, before installing the thermostat or housing or upper radiator hose; this will eliminate any air pockets that have to work their way out after the engine warms up and the thermostat opens. To do this without spilling coolant, get one of those short plastic funnels with the large diameter outlet that's made to fit into a radiator fill opening, drill a bunch of 1/4" holes around the outlet tube, and place it in the thermostat opening in the intake - the end of it will bottom out on the floor of the coolant passage and it will stand up straight. Now you have a funnel to aim at with your jug of coolant, the holes let the coolant flow into the passage, and you can see clearly when the coolant level starts to rise up near the top of the opening. When the coolant level gets near the top, stop pouring, install the thermostat, housing, and upper radiator hose, and finish filling through the radiator opening. When you start it up, you won't have any air pockets, and it will only need to be topped off.
'69 Z28 Fathom Green