I am just glad it worked for you and your A/C is working because summer is hot here and I need the cold air. I ordered the part and its on its way. I am glad that this valve is usable on A/C units and not only the the No A/C cars.

I checked the tube and the old water cock. I noticed the copper tube went to a small piston looking device and i pulled the tip and noticed it would close the valve. My guess is if that copper tube got too hot it would expand something (gas maybe?) in that piston and would automatically close the valve.

My guess is since our part doesn't have that anymore now we have to manually pull the heat back if we feel its too hot in the car.

Here are some pics of the new regulator installed in my 82 280ZX in case some other owners get the same issue.

The regulator:

Attachment 21851

The new one with the wire for cold/hot installed and in both close and open positions, so you can see it works well:

Attachment 21852

Attachment 21853

Some might still have the radiator in the car for the A/C. I had mine flushed out because I wanted to clean my car and also open that rad compartment because it was full of dust/dirt since this car doesn't have a filter for the fresh air that comes in the car. But as the guys have previous said, you can take this regulator out without having to do what I did.