Temp gauge mind of it's own!

[nesty]

I had a bit of a problem with my temp gauge today. I haven’t used my van for about 2 months, so thinking non-constant use might been this problem.

Van started ok (after I charged battery). The flashing temp light doing the usual pre check. Then After about 1 minute the warning light starts flashing and the needle zooms right up to maximum. However I suspected the engine not overheating and it's not.

Then after a while the red light stops flashing and the needle returns to the middle.

However this process repeated itself 7 times. However now it appears to be stable and working ok for now after I took it for a very long run today!

Any ideas what this could be. Faulty gauge or sender?