This happened a year ago and my mechanic fixed it by replacing some wires behind the dash - supposedly.
Sometimes the needle doesn't move at all, sometimes it hovers at midway then other times it goes to high and buries itself for about 3 min. then goes back to normal.

I figure it's one (or more) of three things:
Thermostat Faulty
Fans not operating correctly
Wiring

Instead of replacing all these things I was wondering if anyone here has experienced this phenomenon and had a suggestion for me.
Thanks in advance!

 

Typical thermostat, and/or air bubbles in the system. Wiring or sensor connection loss does not produce higher readings, might cause intermittent lower readings.

Bleed the system first by keeping engine over 2000rpm with bleed valve or one hose ajar. If no help, thermostat cahnge.

 

Thanks Wiking,
Will it cause any problems like it is. I might not be able to get to it for a week or two. Or should I do it ASAP?