I have a 1995 Chevy Tahoe 5.7L v8 350. I’m having a problem trying to get the heat working. Blend door actuator is good and I just put in a new thermostat. Yesterday I put a new heater control value because the old one broke. I installed it correctly but now no antifreeze is flowing from the radiator which is causing the engine to overheat. I can touch all hoses and they are cold. Nothing is passing through. I didn’t have this problem before. Is the valve faulty or is the vacuum line connected to it causing the problem?

 

Might be air in the system, loosen the hose clamp around the valve outlet, bleed what air might be in there,

 

like kevin said, could be air or the thermostat could be faulty. if you cant seam to burp the system then take the thermostat out and drop it into some hot (not boiling but close) water on the stove. see if you can see it opening