Hi,
I called VW Canada for an explanation last week as my new thermostat was
opening later and the engine was running 20% warmer with this one.(see my
page)
http://www3.sympatico.ca/huotx/front_radiator.htm
If you have the letter " F " at the end of the of the new VW OEM part # ,
they open a bit later than the old 87 deg that was opening a bit sooner
than the newer model (both red 87deg). VW says that the engine was running
to cold before. They are full of sh** if you want to know my opinion!!!! If
you have a thermo opening at 82/85 deg it should be written 82 deg, the new
one fully open at about 90 deg.

I have a bunch of old thermostat in a box from different car I did major
work in the pass, I did some test this weekend for the fun of it with a
digital thermometer, most of those open at around 82/87 deg, the # on it
are from 80 to 87deg, they are all fully open at 87 at the most (Honda,
Toyota, Mazda), except all VW one (Golf, Jetta, Fox)

Note: some of the Honda's did open at 75/78!!!!!

The idea behind this is at what temperature an average car or van should
run; most of those cars have aluminums heads������.

My VW dealer gave me a new one to replace the new one!!!!!!!!! And another
free one (slightly different) for testing. (They are very nice but don't
know shit about the vanagon)

Regards, Ben (87GL)
http://www3.sympatico.ca/huotx/engine1.htm

Bus depot sells a cooler one, I don't remember how many deg.