Strange engine temperature guage behaviour

[Sugar Free]

Lately my engine temperature guage has been acting a bit funny. It'll sometimes drop to the baseline (50 degrees) and shoot up to the normal range (90 degrees) again after a while.

It doesn't go above the normal range.

Any ideas? Broken temperature sensor? Broken coolant system?

The car is a mk5 golf tdi.

 

[Sugar Free]

Hmm, so it's not really worth bothering about then?