td,

I am late getting to your post on temps in you 300SDL ... we may have crossed messages in another post, too.

My 350SDL's temp has always been very steady at 82-85C in normal ops including high speeds with a/c off - it had always warmed up a bit in traffic, but NEVER above 100C ... I recently swapped the viscous clutch and replaced waterpump. It then ran very warm (in comparison to previous) ... in my opinion, yours is running too hot.

I later replaced the viscous clutch again AND the thermostat ... ran JUST LIKE IT HAD ALWAYS RUN! Back down to 82-85C in normal ops - rock solid! And, it appears to get up to operating temp much faster than before.

I think the tstat was bad and the system is now performing normally.

Does your temp "wander?" Mine did with tstat bad, but does not with new one.

__________________
George Stephenson
1991 350 SDL (200K and she ain't bent, yet)
former 2002 E320 4Matic Wagon - good car
former 1985 300 CD - great car
former 1981 300 TD - good car
former 1972 280 SEL - not so good car
a couple of those diesel Rabbits ...40-45 mpg