1990 Chevrolet Celebrity

Heater problem
1990 Chevy Celebrity 6 cyl Front Wheel Drive Automatic 75,000 miles

I have owned three V6 Celebrity wagons, but this is the first with a 3.1. On this car, if I drain the coolant, I have no heat after I refill, even though I top it off as recommended with the coolant circulating & the cap off.

I tried bleeding the screw by the water pump,
with engine running and with it off, but hot.

I tried jacking up the car and racing the engine
with the radiator cap off after the thermostat had opened (at the suggestion of a mechanic who had owned one), but no luck.

I tried draining the system, and then refilling it through the heater core hose held up high with a funnel in it. When fluid started coming out of the water pump, I put the line back on, topped off the radiator, but no heat.

Last time around with this battle I finally got heat back by jacking up the car, and hooking up a garden hose to one end of the heater core and then the other, flushing fluid through and out of the core and system. I opened the system in different spots to let the water out, assuming I was possibly trying to get a blockage out.
I put it back together, refilled, and had heat for about a month - that is until the lower radiator hose blew off in a long traffic jam and emptied my system in about 1/2 a second. Could it be that someone forgot to tighten that hose clamp?

Anyway, I'm back at it again, and it's 6 degrees outside, any suggestions on the correct way to do this?
January 3, 2008.

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