Heater Help

squelch · 10-21-2007, 03:30 PM

I have a new '84 Carrera with the automatic heater system. I just got the car, so have never used the heater before. I just went through the whole system and did the following:
1. Got the blower fan in the engine compartment working.
2. Checked operation of both footwell blowers.
3. Replaced control cables to the butterfly valves.
4. Checked operation of the automatic temperature control system.
5. Checked operation of the temperature sensor.

The automatic heater system, seems to work correctly. As I move the dial through the range up to 9, the butterfly valves close and the engine blower and footwell blowers come on. However, with the auto controller in the 0 position and driving down the road, warm air comes out of the defrost duct or under dash duct, depending on the position of the dash mounted lever. When I stop driving, like at a traffic light, the warm air stops blowing, and as I drive faster, more warm air comes in. It is as if if warm air is being forced in due to driving speed.

My question: Is this normal and if not, how do I stop it? I looked under the car and the butterfly valves are open. I must be missing something, but don't know what it is.

Thanks,
Chuck

javadog · 10-21-2007, 03:51 PM

Chuck,

Make sure the threaded rod that operates the lever that pulls on the heater butterfly valves is adjusted to the correct length. In other words, make sure that when the auto heat control moves the lever to close the valves, the valves actually close all the way. Also, check the adjustment of the cables at the butterfly valves; the same line of thought applies. If they are adjusted too tight, they may leave the valves open a little bit.

JR

squelch · 10-21-2007, 08:23 PM

JR,
Thanks for the response. I think I have it adjusted properly. I have the threaded linkage and control cables set so that when the autocontroller is at 0 the butterfly valves are open and as I turn the knob towards 9, the butterflies move all of the way to closed.
The way I understand it, if the butterflies are open (the 0 position), all of the hot air goes out the bottom of the car, so why is hot air going into the cockpit? Is there any way to block off the hot air completely from getting in?

Thanks

javadog · 10-22-2007, 05:11 AM

chuck,

The only way for hot air to go into the cockpit is through those butterfly valves. I'd check the adjustments again, as at least one of them has to be open a little bit.

JR

Mysterytrain · 10-22-2007, 05:22 AM

How hot is the air that is leaking inside the cabin? Will it melt the sole's of your shoes? The reason I ask is that it might be a mis-adjusted front fresh air valves. If they leak you will have 'hot okie' air entering the cabin. Leaky fresh air valves will allow outside air to enter the cabin thru the defroster vents and/or the underdash vents. If there is no hot air coming from the little left and right side dash vents then it is most likely from the fresh air system. The hot air from the heat exchangers is ungodly hot, so there is a difference.

javadog · 10-22-2007, 06:48 AM

Good point, Ron. If we are talking about ambient temp air, and not heated air, it probably is coming from the fresh air system.

Chuck, which lever on the dash do you move to change the output of the air from the footwell vents to the dash vents? The middle black one, or the bottom red one?

JR

squelch · 10-22-2007, 01:04 PM

The air is definitely heated, but is not shoe melting hot.
It is not fresh air, because when I turn on the the dash mounted fresh air fan, much cooler air comes in via the defrost and under-dash vents. If I move the top dash lever to the left to turn off the fan, the air gets hot. Hot air also comes out of the little side vents as well as the defrost or under dash vents.

Quote:

The only way for hot air to go into the cockpit is through those butterfly valves. I'd check the adjustments again, as at least one of them has to be open a little bit.

This quote confused me a bit. Am I correct in my thinking that you get hot air when the butterfly valves close and no hot air when they are open, or do I have it backwards?

Thanks,
Chuck

Rot 911 · 01:24 PM

Chuck there are actually two different valves in the system. The obvious ones are the ones you see when you get under the car that have the heater hoses running to them. But up inside you will also see another valve, the butterfly valve that we are referring to. They may not be closing all the way. These two valves are number 11 and 12 in this diagram:

squelch · 10-22-2007, 01:40 PM

Kurt,
You are the MAN! Now it all makes since. I did not realize that other valve was in there. Thank you for going to the effort to post that picture.

Chuck

squelch · 10-22-2007, 02:46 PM

Gents,
Thanks for all of your input. After Kurts most excellent post, I realized that what I was calling a butterfly isn't really a butterfly valve. A picture really is worth a thousand words. I crawled under my car and saw that an adjustment was, in fact, in order. It is now fixed. Thanks for the help.

Chuck

Mysterytrain · 10-22-2007, 02:56 PM

Squelch, great news..forgive me for thinking you were from Tulsa..that was Javadog. I've never been to Tulsa, its on my list ...but Memphis is the holy land to me!

javadog · 10-22-2007, 07:00 PM

So that's where the hot Okie air reference came from....