Nonusual Heater Issue
 

Hey guys. I am at a bit of a loss here on where I should proceed.

When I got my car it had the standard full heat issue. Replaced that $.50 clip under the dash, and most of the heat went away. Now it seems that no matter what temperature setting that I have the heater on it delivers warm air-not warm enough in the winter and too warm in the summer :mad:

I have vented the coolant several times from projects such as changing my thermostat :mad: but that didn't help.

Where should I proceed? I tried playing around with the heating valve right in front of the firewall, seemed kinda soft, but was unsure where to go. Also could be the actual temperature control unit I suppose.

Basically, I don't want to go around changing random parts so I was hoping for some guidance from the brain trust.

Thanks guys! SmileWavy

Oh, it seems that moving the heater thermostat does absolutely nothing as far as I can tell.

I'm not an expert on the heating system but I did have a heat problem once where my heat stayed on. It turned out to be the Brake Booster Check Valve which has a small port and a vacuum line that goes to the heating system. You might check this to see if yours is broken or maybe you have a slight leak in the vacuum line.

Just my .02 cents worth.........Vern

Check your heater control valve. Disconnect the vacuum line to it and attach a spare line. Suck on the line to make sure it holds a vacuum. If you remove the valve you can actually watch the valve working ( or not) as you apply vacuum.

jmd_forest

Hey I kind off have the same problem, first I replace the clip under the dash and check the heater control valve, the linkage on the valve pop out and since it is spring loaded, it stay in the open position.
I change the heater control valve and it solve my problem. Hey! You could also have the some as Vern, since it is vacuum controlled.
Almost forget about my favorite button. The one under the circulation button called defrost make sure it is not depress. I called it instant heat button, because when depress, it bypass your setting. the Fan gone to high speed, it closed the AC door it turn on your side rear view heated mirror and also your rear window defroster. Even in Florida I have used it a lot off time since I work at night and drive home in the morning (grave yard shift)
Good Luck

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Bud
87 930 black
86 951 black
87 944S white
86 944 N/A red (parts car)
83 944 N/A white (auto)
83 944 N/A black