[68speedalert]

Originally Posted by FarmTruk

I don't think you'd want the heater core being supplied by the intake. That would seriously slow down engine warm-up. No use supplying cold water to the heater core. Once the water is warm, the thermostat opens, flowing warm water thru the system, and presto...warm air...

Sorry FarmTruk, but you couldn't be farther off.

Water circulation on a Chevy V8 goes from the waterpump, thru the engine block and up to the thermostat. Coolant goes out the intake, to the BOTTOM connection of the heater, out the upper connector and returns either to the waterpump or the radiator, where it is repumped by the waterpump and so on and so on.

Once it gets warm enough for the thermostat to open, then the coolant goes thru the upper hose into the radiator and so on and so
on.

timcos,

Are both heater hoses hot? If so, you need to check the blend door.

Do you still have a coolant shut off valve? It should be open unless you have the a/c on max (recirculate).

If the hose coming from the intake is hot going into the heater and the hose going to the radiator is cooler, your core may be clogged. Take a garden hose and adapt it to it and flush it out from both connections.