Hi there,

After my experience last week, I'd recommend the OEM-style, or Ranco H-type as it is also known. I was thrilled by the way it worked compared to the one I removed with the dead thermostat.

I thought I had something really special I'd salted away new-old-stock from an ebay auction years ago, but I just noticed IPD lists the valves once again for a shocking $162.

After pulling the old one, and before installing the new one, I compared the two side by side, to see if I could tell the difference. I could not, by blowing through it and operating the control. Both seemed to throttle my breath in like manner, open and close completely.

So, I was pleasantly surprised by the full range of stable temperature that resulted - set it and forget it, compared to the binary freeze or bake unit.

I've never used the Scan Tech type, which I understand is the same you'll get from the Volvo dealer, so I can't discount that. But I figure the wax thermostat, sensed inside the plenum, does such fine adjustment on the valve opening, it would be hard to beat it with a straight valve control.

First you've got to replace your coolant thermostat. It is probably broken inside and running wide open. Fix that, then work on the heater valve.

Don't overlook the possibility of adjusting the heater thermostat with the screw. They aren't all dead, as I discovered on another car. Try the adjustment first, because it is much easier than replacing it.





Here's my new baby. I love the way it works.



P.S. - Your car has LH3.1 if the AMM has only 4 pins on its connector. And it is a stick.

--
Art Benstein near Baltimore

Generally speaking, you aren't learning much when your lips are moving.