Temperature gauge oddity

[beavor-bob]

Once old Veccy gets going, the gauge normally gets to 90deg - & stays there, but on a run today, I noticed around 15 miles down the road (it had been on 90deg) - it had dropped to about 70 - it stayed there until I could pull into a layby - I stopped the engine & had a look under the bonnet - everything looked & smelt! normal - coolant level OK etc (For a Vectra!) Restarted engine & it went straight to 90deg - & has been there ever since.
Any answers?

[horaa]

It's a opel, hiccups are normal. You know, just pretend you are at a doc and he says monitor the issue.

[northpole]

you might want to take off the connector on the cluster, clean it and put it back. It should sort it out.

[beavor-bob]

you might want to take off the connector on the cluster, clean it and put it back. It should sort it out.

If it does it again, I'll try a new temp sensor (easier to get at) I guess the instrument cluster connector, will be a beast to get at? But many thanks for your reply.

[northpole]

No it's easy I suggest you look it up