I have two Chronic leaks. One is rear mains; crank and transaxle must be removed to get to it. My crank has a bad journal on #5 mains so it needs turning, anyway. The sealing surface is scratched from trying to get bits of old seal out. I will also glue a round, lip-type seal over the crank end. A pro wants $1800 to fix that One seal--not even replace crank. .
My other car is leaking somewhere from bottom. Cant even see it. I have to use the fluorescent dye and lift engine 2" just to find where it's coming from. Might need new pan gasket, that's the time to replace it, when I can Get to it. If rear mains bad, too, not Too hard to take transaxle off to replace it. Again, when motor partway out, then is the time to do it all once, right.
I don't believe in those snake oil fixers. Wont stop broken gasket or burnt seal from leaking, and can clog up oil passages.