Hi all thanks for the info and a big thanks to DARREN for reminding me of Mr Robert Boyle, the cooling system was under pressure but as the engine got hot the new filler cap started to leak and the pressure dropped to 3-4 PSI so removed cap and fitted pressure gauge in place of it, at 10PSI and 104.7' on live data the fan came in, Must have done to much technical work yesterday was getting late and my head was up my ass,