Given all the possible problems with inaccurate calibration, perhaps the 
best approach with temperature gauges is to monitor big changes and ignore 
absolute levels. Assume all errors are constant!

For what it's worth, oil temperature with a sump mounted sender on my 1973 
Westfalia is usually around 80C, occasionally rising to 100C for brief 
periods - UK Summer, air temperature 20-25C.

When do the auxillary heater articles begin again?

David Tonks
1973 Westfalia (UK)