Temperature Sendor Replaced but running hot

[mightyatom]

This is to close off the thread as the issue is now resolved. The NOS temperature sender from American Classics fixed the issue, and is now running no higher than mid-gauge. The last update in this thread said it was running too hot again but this we due to air in the system. After back-flushing the cooling system and refilling I did not see the overheating issue and have driven on a few longer trips now.
When I refilled after the back-flush I made sure I was parked diagonally on an uphill slope. I also put the passenger side wheel on a ramp so the radiator cap was the highest part of the cooling system to ensure all the air was out. I cycled a few times of fill, run till hot, let it cool. After this it ran fine.

Neba also contacted me and he has had a similar issue with the Kragen(O'Reilly) temperature sender (Part#WT231 - I think). He has added a 50ohm resistor which get it running a quarter up the scale.

I would never have thought that new temperature senders would be the cause of the issue. I guess the lesson is, don't take anything for granted.

Many Thanks for everyones help on this. You guys are awesome.