longhorn294


Anyone have any ideas on why hot air keeps blowing through my a/c-heater vents while driving my '71? I disconnected the heater water hoses but that didn't make any difference. HOW CAN I STOP IT! HELP!! (2nd post of this message...got in the wrong section)

The heat is comming from the engine and exhaust. Check all the seal to the firewall, heater box. Something is leaking through that area. Be sure not to confuse the heat source with heat radiated from the floor, which collects under the dash and seems to come from the vents.

It's definitely coming through the a/c-heater ducts. It's really hot to the touch on both sides under the dash. Could it possibly be a vacuum problem? Like, maybe something's not closing?

Yes, but you still need a heat source. And that's either the engine and exhaust, or the coolant in the heater core. Are you sure the coolant valve is shutting?

Yep...I disconnected the heater hoses totally from the heater and ran a hose from the water pump up to the intake, bypassing the heater core.

Here are some of the things I checked for when I had the same problem.
Check were you have your air flow set, bilevel, heater, defroster etc. If you have your fresh air vent open engine heat will come in and it seems that it's through the heater. One item that I replaced was the clutch rod boot, that was allowing heat into the car.
I would also make sure that your control valve is actually working.
Rather than disconnect the heater hose I used shut off valves. I don't know about the 71 model, but on my 74, I had to close 2 hose's, otherwise the heat still flowed and eventually backed up and leaked out.

With both turned off, heat still comes through moving down the road.

I would really suspect an exhaust leak where the headers meet the exhaust line. In Ian it was leaking there because there is a valve that is supposed to open up but wasn't. we had it replaced at Midas for about $50. It stopped a lot of heat from coming in and then a shutoff valve I installed in the heater line stopped all heat from coming in. I think it was called an actuator valve.


|UPDATED|9/15/2004 7:19:14 PM (AZT)|/UPDATED|

go to the "interior forum", go to "answer cockpit heat" dated 7-9-04 started by anips and read snoopy's post

Thanks for all the help guys. I didn't realize how many post there were about this problem. Definitely got some good advice and I'm still reading! On the other hand, if I don't get it fixed soon, in another month or so that heat will feel good! Not today though. It's 98 degrees and the humidity feels about the same! My lawnmower repair shop slows down in the winter so I'll have plenty of time to tear into it. Let you know when I find the right fix.