I have tried and failed to get rid of all the
oil leaks in my FE.
First I removed the transmission, clutch, flywheel, and block plate and added dye in the
oil. Cleaned the back of the block thoroughly and ran the engine until it was hot. A black light showed the leak was from the side seal on the rear main bearing cap. I fixed that. I apparently didn't do a good job on the
oil pan gasket, though, so later noticed that was leaking.
I replace the oil pan gasket. It is completely dry.
Both valve covers were leaking, so I replace those. Fixed.
When I had the transmission out and dye in the oil, I looked at all the plugs in the back of the engine carefully. No sign of any leaks.
I have looked at the intake manifold all the way around. No sign of any leak.
I still have a small leak that runs down the block plate and drips off the bottom. The bell housing is dry inside. The small leak looks bigger than it is the way the oil spreads on my epoxy garage floor.
I hate oil leaks, but have just lived with it rather than pull the transmission (seats, tunnel, flywheel, etc.) again. I just don't know where it is coming from, even after having been under the car many times with a bright flashlight. I'm thinking about the diaper approach.
I really hate leaving an oil spot on someone's driveway.