Cadillac Repair: How difficult is the 94 STS to work on?, dowel pins, head gasket

Question
STS from uncle's estate. Leaking coolant rear of engine apparently between engine and trans. Told might be freeze plug, also that STS very complicated and expensive to work on. Twice as long to separate engine and tranny to check because so much involved. (Snake cousin willing to take of my hands cheap, for some reason.)
How many hours to eye ball problem, any guess what else might be wrong, Engine runs strong

Answer
Hi Tom,

    It's been awhile since I had a northstar engine out and it is quite an ordeal. The first one I did I separated it from the trans inside the car. What a shoehorn job...not much room to slide the engine forward in order to get it away from the torque converter nose and trans dowel pins...that I had to remove the harmonic balancer to gain the room I needed. And when retorqueing the bolt to 230 ftlbs aprox. there is a special holder so the engine doesn't move. That is important because the oil pump drive gear is sandwiched between the balancer and the crankshaft and if the bolt was loose then the oil pressure could drop to 0 and then engine damage would result. The other 5 times, and since I had a hoist, removed the engine and trans along with the subframe as a unit after separating things and raised the body up leaving the powertrain sitting on 4 jackstands. Then there was room to separate the engine from the trans to work on it. If you have access to a hoist you could take the trans out the bottom first after removing the engine cradle/subframe in front, Then see where the leak is. I would allow 20 hours if replaceing the engine. I know it sounds like alot of time but from someone that has done it it isn't an easy job. Otherwise 7 hours for a trans R&R.

      These engines are known for head gasket failures due to head bolts stripping out in the block. Also the waterpump and coolant manifold is back there so those are potential leak places.

      I would definitely start with a cooling system pressure test to see for sure where the leak is. If still inside the bell houseing area then remove the upper intake and starter. Then useing an inspection mirror you might be able to see where the leak is. Good luck, Bill