Grand Caravan heating problems

[jakuzi1]

I have a 96 Grand Caravan that I am experiancing heating problems with. I had the radiator flushed and replaced the thermostat. I let it breath for 45min by running the car while the radiator cap was off but it still has no heat. Well, very very little heat. There is no leak in the heator core. The blower and everything else works fine. The vehical does not run hot or cold. I just can't figure out why I can't get any heat. I thought the heator cores leak when they go bad otherwise they don't really go bad. Does anyone have an ideas?

[jsinton]

They will have some sort of heater control valve which allows hot water to flow into the heater core. Probably it works via vacuum from the heater control switch. So without knowing, I would say either you have a vacuum leak or your heater control switch is not working right.

[Bernard Feltzer]

Did you have heat before the flush?

[jakuzi1]

No, the heat was pretty much the same before I changed the thermo and flushed the system. In fact the heat is what prompted me to do those things. I know the vents work on vacuum but I don't know anything about a switch. If it were vacuum problems would I not see problems with the cruise control and other vacuum controlled things? I am not seeing any other problems.

[ronmar1]

Warm up your engine to operating temperature, turn on the heat to hot, feel both hoses where they go through the firewall to the heater coil. They both should feel warm to hot. The supply hose should be hotter than the return hose. If one is warm to hot and the other is cool then the heater core is blocked or the operating valve is not working. If it has an air block, you can carefully disconnect the return hose from where it goes through the fire wall. Pull up just slightly higher with the hose and add water or coolant till it runs out both the hose and the heater core stub. Re-attach and try it now.

Hope this helps.

Ron