300TD refuses to get too hot - Good or bad?

[81Wagon]

I drove out to Las Vegas on Tuesday and came back yesterday, and I noticed something a little funny with the coolant temperature.

On the way there going up a fairly short grade which I drive a lot the temps didn't pass (or even reach) the 100 C mark, though it usually gets to about 105 by the top of that grade. I thought maybe the car was having a good day.

On the way back I had to drive up a very long grade on the I-15 just out of Nevada. The car performed much better than usual - I didn't drop below 75 and I didn't have to move out of the fast lane :-). However, this still required me to floor it the entire way up, and my EGT showed about 1200 degrees the entire time (normal on grades like that) so I was completely boggled when, after four or five minutes of this, my coolant gauge was still reading below 100 C.

Is it possible? The outside air temp was 63, not too cool. Is my temperature gauge or the sensor maybe messed up? The gauge reads totally normal, just what you'd expect, under normal conditions; it's just that it doesn't seem to want to go beyond 95 C.

On a different note, on one of the long, empty downhill stretches of the desert I got my wagon up to 5200 RPM... somewhere between 105 and 112 MPH (damned 85 MPH speedo...). It ran and idled incredibly smoothly after that - I haven't started it yet today but I hope it stays that way!