What are you referring to as high temperature? The stock Thermostat rating is 87C, (188F). That is plenty and should be used all year. From experience, the most consistent acting and best response are the ones from the dealer. (???). Of the features of the part the top control disc has a rubber gasket to ensure no leak by when it is closed. Next choice would be the Wahler, (German). I have had some Mehle that fit but they may be coming from unknown sources. If you do go to a parts store, almost all will sell you the wrong stat. The lower disc will be the wrong diameter. If the listing includes some Audi or other vehicles it is wrong. 

The confusion comes from the practice that T-stats get listed for vehicles based on just a few specifications. Usually the top housing diameter is the key. Vlave types, bypasses, bleeds, lengths and other features get lost. This is a real problem even in American vehicles, trucks, RV's that need stats with more flow and thus use a different design such as umbrella instead of disc. The wrong stat may jam partly open and/or not open far enough for proper cooling. 

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of Mike Riley
Sent: Wednesday, December 12, 2012 9:49 AM
To: vanagon@GERRY.VANAGON.COM
Subject: high temp thermistat

anybody have a recommendation for a source for a high quality high temperature thermostat?
mike