fitted a 1.6 cvh engine in my mk3 escort new stat fan switch temp sender etc but fan cuts in right in the red and only for about 5 seconds is it possible i have a defective fan switch i thought the fan normally cuts in around 3/4 on gauge and stays on for atleast longer than 5 seconds . heaters blow hot so dont think its airlocked coolant level not dropping tried with stat out still same but takes longer to get hotter top and bottom hoses hot