The temp guage will also drop when the fan cuts in.

Thermostat new and boil in pan tested. Temperature rises to around near middle and can drop relatively quickly to only just above the first gap, then rise again and fall. It's the big change in temperature and the speed that's qute striking and it did not do this before flushing and renewing coolant. Done everything possible to try bleed the system. Doesn't seem to be causing over-heating or anything so I'll leave it until it does.

Thermostat new and boil in pan tested. Temperature rises to around near middle and can drop relatively quickly to only just above the first gap, then rise again and fall. It's the big change in temperature and the speed that's qute striking and it did not do this before flushing and renewing coolant. Done everything possible to try bleed the system. Doesn't seem to be causing over-heating or anything so I'll leave it until it does.

describe how you bled it?

I find that the heater matrix in Felicias/favorits are bloody huge for the engine size- conseqyently, its common to get a lot of air trapped.

I'd run car with cap off expansion tank, and massage the coolant pipes into and from the heater, and to and from the rad.

Checked all hose connections etc, filled slowly in expansion tank up to max level and ran engine till warm and fan cut in. Let cool and topped up. Ran again and once up to temperature, squeezed the hoses, revved it for a while (that seems to get the heater matrix going faster) with cap off.

Most recently took out the thermostat temp sender and when I took off the expansion tank cap realised I had a fountain, put cap back, topped up inside hole vacated by temp sender, replaced with new washer. Thinking behind it was if the level isn't constant it may not heat the temp sender constantly. Then back to running engine till warm and fans cutting in etc and squeezing hoses twice.

It's the big change in temperature and the speed that's quite striking

Yes, it doesn't really fit in with faulty stat or airlock? More like a faulty sensor (giver) or some fault in wiring - contacts (bad connection, short-circuit) or even the temp gauge?

Yes, it doesn't really fit in with faulty stat or airlock? More like a faulty sensor (giver) or some fault in wiring - contacts (bad connection, short-circuit) or even the temp gauge?

could be something in that thought:D:thumbup: