Could it be because the indicator marks on your white dials are slightly out of line compared to the original ones ?
Meaning the needle doesn't line completely up with certain lines/dashes on speedometer, rev counter etc etc
Hi I do not think it is from the white dials since it worked great about 6 months without any problems so far.
Let me briefly state what happened
Two weeks ago, my temp dial needle hit almost the 3/4 of its scale then I took the car (Mk1 RS 172) to the dealer. They decided to change the thermostat and temp sensor just for the starters. Though clearly that did not solve the problem. We checked the water temp by CLIP and observed that there is not any overheating problem. Fan also cuts in regularly when needed. Now when I do the self test of the speedo I can see that temp dial is way off with different amounts when the ECU sends 1/4 1/2 and 3/4 signals . (at 1/4 and 1/2, dial shows higher values whereas for 3/4 and H less values) I took the speedo off and plugged it to another car and it worked OK.
Where else could be the problem.