Here's what the beast looks like:
The valve works off a dash-mounted cable, which moves a plunger in and out of the tubes, blocking the flow of water to the heater and defroster cores. There's only one part to replace by this process--a rubber seal--but you have to take the thing apart to do it. Let's get started.
First, we remove the spring off the back:
Then the clip that holds the plunger against the controlling arm that moves it up and down.
After that, it is a matter of straightening out a series of tabs to separate the housing from the valve--here's the top section after it has been removed. The large, black disc on the right side is a rudimentary automated temperature control, which expands and contracts, adjusting the valve to regulate the temperature.
|The seal is on the left side--looks like it has leaked before.|
Still more tabs to remove to get access to the valve.
|Looks a little better after a little touch up with a wire brush.|
Here's the valve in place with the new diaphragm in place:
Then the temperature regulator is put in place...
Followed by the lower case, clip, and spring. Now I just need to find 2 number ten sheet metal screws to mount it to the firewall. Since this is all hidden by the dash and protected from the elements, I didn't bother to paint it--chances are I'll have to replace that valve again in a few years anyway.