Sitting on the M25 this evening, my T4 was getting quite hot - the temp gauge normally goes up to one bar off the red before the fans kick in (non-standard i/c and rad and fans). It did this, and the fans started to cool it, but then strangely the external temperature display wandered up from 21 ambient to 44 (!) degrees. I got a bit worried so whacked the heater on and turned the ac off, and the engine quickly cooled back to normal 3-o'clock position on the gauge, but the external temp stayed up at 44. Even when I was moving at 40mph again, it was stuck up there, and it was only after a few minutes that it suddenly dropped down again through the range back to the correct ambient temp of 21.

Odd!

Anyone seen this before?

Is 44 degrees the "top of range" reading for that sensor by chance?

I checked and the sensor is still on the front of my car (so we can rule out someone nicking it...!)