no heat help!

[jamon8]

just drove my 83 grand prix home for 250 miles without any heat

I saw that there was a vacuum line going to the heater hose what is that for

thanks

will post pics if nessecary

 

[bill]

just drove my 83 grand prix home for 250 miles without any heat

I saw that there was a vacuum line going to the heater hose what is that for

thanks

will post pics if nessecary

The vacuum line connects to a valve that opens and shuts off water to the heater core. If its unhooked, you wont get any heat because the valve needs vacuum to stay open. Turn on the heat and put your finger over the end of the hose...you should feel suction. Connect the hose to the valve....if you have enough coolant in the system, you should get heat. Good luck

 

[Bonnewagon]

I thought that water valve worked the opposite way, it shut the hot water off when the AC was turned on? Either way, maybe the vacuum line for the dash ducts is missing or the ducts are stuck closed or the vacuum reservoir/amplifier is broken or missing. It's that black ball near the heater/AC components. When you shut the car off, try moving the heat controls. There should be enough vacuum to operate them a bit before the vacuum is lost, and you will hear them moving. At operating temps the hoses to the heater core should be hot. If not, either the core or hoses are blocked. If that's the case try backflushing them out. Is there a proper thermostat in the motor? It may be stuck open.

 

[jmt455]

I think Bonnewagon is correct; you should still have heat if that valve is not connected to vacuum supply.
Sometimes people disconnect that heater control valve because the valve would leak...
That happened to me on my Caprice wagon; hose was disconnected when I bought the car. When I connected the hose so the heater valve worked, the valve started leaking. Replaced the valve and I had cold A/C and no leaks.

I agree with Bonnewagon...verify that your A/C controls are moving and check the thermostat.

 

[Blake442]

The temp control cable frequently breaks where it attaches to the heater box.
This can leave you stranded with it set on cold, not allowing any of the air moving thru the box to be warmed.
Drop your glove box and you can clearly see where the cable attaches.
If it doesn't move when you adjust the temp, there's your culprit...

 

[bill]

I stand corrected....forgot about the ac cutout scenario.... :lol: