Heat Valve Problems

[dgarrood]

No heat at all in the car which is equipped with Auto Heat. Heat valves are in a position where all heat is dumped outside and passages forward are blocked which is the default position maintained by springs. Took apart center console and found linkage rod between servo motor and lever off, in fact the plastic end was split. Tried moving the lever by hand - it required lots of force! Took the springs off the heat valves and made sure they worked from below with minimal force. After this the lever was also easy to move through the full valve range from open to close. Reinstalled the springs and it was hard to move the lever again - too hard!.

Question: Are the springs on the valves different between the auto heat and manual heat cars? If so, do I have the incorrect springs on the car? I tried looking around for any info on the spring but no specifics.

Lacking further information, my solution is to go down to the hardware store and get a couple of weaker springs and install those hoping I can find a compromise between reasonable actuation force and the default no heat action made possible by the springs.

Any comments are appreciated

[Flat Six]

Originally Posted by dgarrood

Question: Are the springs on the valves different between the auto heat and manual heat cars? If so, do I have the incorrect springs on the car? I tried looking around for any info on the spring but no specifics.

Heater boxes and springs are the same regardless of autoheat / backdated heat. Had the same issue as you; ended up cable between autheat controller and heater boxes was sticking inside its routing tube in the center tunnel. This additional resistance along the length of the cable makes it feel like the heater box springs have too much tension. My solution was to use liberal amounts of PB Blaster on:

a) heater box springs
b) heater box dump valve pivot points
c) down the cable tube from under the car, and
d) down the cable tube from inside the car (other end).

With the lever disconnected from the autoheat servo motor, manually push the cable back and forth inside the housing (from under the car) to release whatever gunk might be creating additional friction. That's what worked for me.

If your cable is kinked or frayed inside the tube, you might have to replace it entirely.

Hope this helps.

[dgarrood]

Thanks Flat Six. I will try the cable lubrication. The valves work freely after being "blasted".

[DRACO A5OG]

My cables stretched over the years and was not completely closing the flaps which are located on the bottom side.

I had a helper raise and lower my levers as I adjusted the lock nuts for the cables at the flaps.

Take care, they may be rusted so I just twisted the cables at the nuts to take up the slack on the cables to allow the flaps to close when levers are all the way up.

I now have full heat as I need it.

Also ,I did spray some lube up the shafts of the cables for extra measure.