I have recently purchased an '82 Vanagon that has a new engine. The shop that 
built it (I would have rather done it myself) installed a head temp. gauge and 
told me that 350 was normal and 450 means slow down. I have found that 400 to 
425 is the usual temp around town and it climbs to 450 on the highway at 
60-65mph. Climbing mountains causes it to rise to 500, at which point I slow 
down. BTW, I am not lugging the engine. All the other VW's I have owned have 
had the T1 engine and I am at a loss with finding any head temp data on the 
T4. The dealer in my town is staffed with idiots (they suggested removing the 
gauge), and I have not been able to find two mechanics in town that can agree 
on an acceptable normal running temperature. I seem to remember my old drag 
car (1835, 150hp.) running around 350. Does anyone know what head temp a T4 
engine should run at? I know of the cracked head/ dropped seat problems these 
engines have as I am a VW mechanic myself, and would like to avoid this. Any 
help would be greatly appreciated.
_______
"Get these rabbits the hell
 off of me!" - Something I yelled
and woke myself up with a while back