I had this problem in my EF.went to mechanic and he changed the Oil switch.it worked for me.

OP, slaving on this thing in 35 deg heat in Melbourne, one or two people who commmented about tensioner housing and plug leaking, are right, thats the origin, even though it seems to originate down bottom right cnr of water-pump..

water pump bolts are mostly wet oil on threads, dont really understand that, but oil is leaking out of thast tensioner plug, free-falling down to that space between water-pump and bottom drivers cnr of TC

Trick was, removing water pump then gave perfect view of what was going on..so now have job of sorting out gaskets on old daggy water-pump..

after the plug is removed how do you release the tension on the tensioner without the ford tool?, also it looks like you need a special tool to undo the tensioner bolt as it is not hex head and only has 2 small holes in the end ? , cheers