Hello,

A year ago, I needed to replace the thermostat in my '88 Mazda.  I was
horrified to see that the OEM thermostat was actually a dual: one about 3/4
inch and the other about 1/4 inch sitting next to each other in the roughly
1 1/2 inch circle that we are used to seeing.  The shop manual says that
the tiny valve opens at 180 degrees F and the big one at 185 degrees F if I
remember correctly.  The Japanese aren't afraid of complexity.

So, I searched around and every FLAPS that I tried said that they not only
didn't have such a thing, but there was no such thing.  A web search
located the wisdom that the dual thermostat was essential in a Mazda, and
never to use anything but.  So, I spent the bucks and got one from the
dealer.  It was an exact match.

Now, a year later, the replacement failed.

So, I thought about it for a bit and decided that the only thing that the
dual thermostat could do was reduce the gain of the feedback system a bit.
 The reason that that might be done is to prevent the temperature from
hunting up and down.  So, I bought a Stant after market thermostat and
decided to watch the temperature gauge for signs of hunting.  The gauge
appears to display exactly as it did with a working Mazda thermostat.

I say all of this because an after market thermostat for our Vanagons might
be fine.  Perhaps some of our trusted parts suppliers on this list are
selling after market thermostats that they have determined to be correct.

Thanks for listening,
Mike