W211 Flickering on dashboard engine temperature gauge .

[W1ghty]

On the E320cdi ,2009 W211 . There is a flicker which isn‘t continuous on the engine temp gauge .
Its been going on for some months , I just keep forgetting to look into it .
The flicker only affects that right hand gauge
It doesn’t happen all the time .
Lights on or off makes no difference.
It possibly occurs more when the car has just started but also crops up at any time throughout a drive .
The temp gauge always reads correctly and never budges .

Any suggestions as to where to start looking ? Maybe some connection cleaning (he says hopefully)

There are no fault codes

Thanks