Hi all, i have an insignia 1.8 petrol, the other day i didnt screw my coolant cap down correctly and lost probably half of my coolant, stopped the car straight away, rang the misses to fetch coolant, filled up and away i went back home, since then my radiator fan has been on ever since, i have replaced the themostat including temp sensor and a new expansion tank, i have noticed that the coolant return pipe doesnt seem to be returning coolant correctly, any ideas?