Ford mondeo mk3, intermitent dumping of water from cooing system,found crack in header tank, changed same,ran car at idle, temp guage at normal & heater blowing hot , took car for run , temp guage off scale blowing cold , drop back to normal still blowing cold, then warm , temp guage swinging from norm to high sporadically

I have a mk3 mondeo cooling fan wont cut in checked relays and they work replaced thermostat replaced sender sensor i have power going to the relays but just wont cut in?

You may have an air pocket in your system which some times happens.  One way to get rid of it is to take the upper hose off on the engine side,  fill your system with water until it runs out from your engine block, replace the hose, start your car turn you heater on and set to hi keep the radiator cap loose until the temp start to rise then close tight.  Once the air pocket had been remover you can drain some of the water from the radiator using the lower drain plug and add antifreeze.