Ventilation Repair - Part 3 - 03/06/2016

In the continuing saga of "old cars and stuff that breaks" we were graced with the heater valve ceasing to open again. I did a quick fix on this last year when I bought the car (see part 1) and it held up without too much trouble for the year since then. But then it stopped working again so it was time to do a more permanent fix.

I removed the entire slider assembly this time. The heater valve and recirculate function are controlled by the bottom left wheel. This one was VERY sticky, so a little PB Blaster and grease fixed that.

When it's full cold it has a plastic lever that it moves along with a notch at the end for recirculate.

And slid all the way over for full heat like it should.

This is where the problem was: the plastic has give in it to avoid breaking. When the grease hardens and the slider wheel stiffens up, it takes more effort than normal to slide the plastic guide along with the metal rod, so the plastic pops off the rod and ceases to function. This leaves the heater valve and recirculate functions in whatever position they happened to be with no way to change them (in my case, stuck closed for no heat). Oops. New grease and lubrication keep this from happening and it slides extremely smoothly.

The diverter door selector also needs lubrication and cleaning. There is an ambient temperature sensor above the lever that must be removed.

I also cleaned out the grime and gunk from the slider bar and the detents used to indicate the proper position. This way it will be easier to find which position you want and slides cleaner and easier (less chance for something to break!).

Not a bad amount of work, pretty easy. Cheaper than buying a new one! Put it all back together and it works perfectly and slides better than it has in probably 25-30 years.

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Last updated March 6th, 2016