GTO3 Temperature

[MadMacMcMad]

Gents
My temperature guage has always read around the 100deg mark. This has never worried me as the guages are not that accurate and the fans always cut in if the temp rises further.
Recently, I have had to top up the header and this morning, the guage suddenly dropped to around 80, then back up to 100. Any clues ?

[art411y]

not the noble but my escort cossie did this and it was a sticking thermostsat.changed it and was steady at 80 degrees