Geezer Nug wrote:
It's all fixed and working nicely.

It was the coolant temperature sensor. 'We sell a lot of those' said the
spares chap...

Haynes BOL says to drain the coolant, but a plastic bag over the neck of
the expansion tank with the cap screwed back on stops much escaping.

I measured the resistance of the new one, it was 27K ohms. Just to prove
the point I measured the old one once it was out. I was gutted to find
it read the same. Carried on anyhow and measured it a while later, this
time it was 40K, so it was an intermittent fault.

Many thanks and much kudos to Tim, who diagnosed it in one. I owe you a
beer sometime!

Cheers
John

--
How I hate this damn PC, I think I'm going to sell it.
It never does quite what I want but only what I tell it.