i have an external coolant leak on my 92 explorer 4.0. hoses are ok. don't see any leakage around water pump. it's dry below thermostat housing. i haven't climbed under yet, but coolant (after driving) is dripping from somewhere towards the back of the engine, at least half way up the block. i'm going to try checking the engine block drain plugs and the core plugs, but where are they exactly? thanks for any help.