Still got no heat. Pulled the vacuum line off my heater valve. When on 'cold' inside, there is vacuum pressure. When on 'hot', there is no pressure. Only the bottom water line back to the heater core is so hot you can't touch it. The 'top' line is not nearly as hot (from the core back to the valve). Is that a bad valve, or is my heater core plugged? Which way does the water flow thru that heater valve?

------------------
1988 Firebird Formula, 305 TPI, K&N filter in 'hole-y' cannister, MSD coil and wires, Accel cap, Monaco seats

 

I don't know were your heater control valve (HCV) is located but i installed one on my 84 Z28 to help with eng. cooling during the summer months. I installed the HCV inline on the heater hose that comes from the int. man. This would be the hottest water returning to the stat houseing. Because the water pump is a suction pump it sucks water from the int. man. through the heater core to the water pump. Why don't you remove the HCV and install a piece of pipe with a couple of clamps and see if you have heat. If you do then bench test the HCV by applying vac. to the valve to see if it works. If it works then you have a proublem with your dash heater controls. Good Luck.

-Auggie-