i have a 460 ford motor and it is in the car. i put all new freeze plugs in when i had it out. when i got it running there was a leak right behind the motor mount in one of them. i drained the water out and put in some k & w block sealer ran it for 30 minutes, like the can said and it stopped. i drained it out and opened all the drains, hoses and the thermostat housing. the only ones i couldn't were the screw in ones at the bottom of the motor, on each side. they are a allen head type. they wouldn't turn, as usual. i need to get them out since the water must be out below them for the sealer to dry and cure. i could remove the mounts but it is a real pain to do. i sprayed pb blaster for several days with no luck. i can't use heat because there right above the oil pan. does anybody have an answer to this?