Hi,
my '91 245 had been showing 'cold' on the temp gauge for a while and I had the thermostat replaced by a good volvo indie mechanic. We discussed the symptoms and he knew about the whole compensator board issue. Immediately after he did it (late Fall) the gauge read 9 o'clock. But within a week it was back to it's old position around 7:30, sometimes going down to 6:30. His take was that if the car made 'heat' sensed by me through the vents then this was a version of the compensator board problem but basically not a big deal. Things smoothed out and in my normal commute it has been sitting around 7:30, but blowing lots of heat.

This past week as the air has become damper (I am in VT) and warmer I have noticed the following behavior during my daily commute (15 miles each way).
1. Early in the a.m. the car warms up gauge reaches 9 o'clock.
2. Gauge reads 9 for 5 mins or so (speed/distance don't effect it)
3. Gauge drops to 6:30-7. Stays there for remainder of trip (10mins).

Often, if it has been warm (around 30F or higher)during the day the gauge won't get above 7 o'clock all the way home.

This doesn't fit with the wilder fluctuations most people report due to the compensator board problem. Other things I have begun to think about include the sensors.

Any advice?
cheers,
Rod