1993 Chevy Suburban V8 Two Wheel Drive Automatic 150000 miles
I am trying to track down the problem with why I have no heater, I have replaced the thermostat, radiator, upper and lower hoses. I noticed that all the radiator hoses get hot and pressurized after driving except for the heater hose coming from the firewall that attaches to the heater core, this hose never feels hot as it should if hot water is traveling to the heater core for the heater. What could be causing my heater not to work? It is my understanding that if the heater core fails, it usually leaks water into the passenger compartment, is there another device that controls heater fucntions that I should look at?
The heater core can be plugged and not leak any coolant into the car. Now, with the engine running, hot, and the heater on high, do both heater core hoses get hot? If not, chances are the heater core is plugged. Remove both the inlet and out let from the heatercore at the fire wall. Using a garden hose, see if you can get water to flow through it. Do it in both directions so you actually backflush the core. If the water flows freely, the core isn't plugged.
If that is the case, check the blend door. It is the door that determines if you get heat or AC to the cab.