I am working on a 1997 F-150 with a 4.6 in it. Yesterday it started leaking coolant from between the rear of the motor and the auto bell housing. I thought at first it was a freeze plug so I pulled the trans. and found that the two freeze plugs were fine that it was leaking from a third hole just above the rear main seal plate that looks like a freeze plug hole but instead of a metal freeze plug it had a plastic cover (inspection or dust cover) that is shape similar to a freeze plug. Is there suppose to be coolant in this passage if so how did the plastic cover keep it in this long? As soon as I put coolant into the resv. it pour out of the hole. Any thoughts?

 

Its probally a heater hose that runs from directly behind the water pump, under the intake to the heater core.