i want to measure my oil temp but don't have a fancy VDO temp sender, etc.
But i do have fancy temperature probes that are just a small wire i can
put anywhere (type K thermocouples). I would be happy to snake one into a
coolant line (like SeanB did once upon a time) but am a reluctant to do
that to an oil line as the consequences are much more sever if it
leaks....

so what about strapping my thermometer to the body of the oil filter? I
know the oil cooler is there, but my logic is that after a while, the
whole system is in equilibrium and the coolant won't cool the oil THAT
much, right? i mean after a while, like an hour or so of driving.

The motive of this research is two fold. I recently installed a cooler
thermostat and radiator fan-switch and would like some date to support out
hypothesis that is the the correct system for these rig's.  And the second
point of note is this from driving this past weekend. The ambient
temperature was between high 20's to high 30's. When cruising along at
highway speeds, after about an hour the front heater would start to loose
it's burning hot air but instead more a mild heat would come out.  I had
the rear core open and the rear fan on the 1st setting.  I had the air
flow on FULL in the front. To get more heat i would throttle the front air
to 1/2 or 2/3 off.  My concern is it may be running too cold. The
ever-so-accurate needle on the dash sits steady at 1/2 high at all times
once the engine is warm.

the books i have on engines always say the ideal oil temp is 109deg C.

Thanks
matthew
86 syncro westy tiico