I have the engine out to do some other work in the bay, so I want to clean up some oil leaks if I can. My original plan was to simply change the pushrod tube o-rings and MAYBE the rear seal, but now that I've started pulling the tin I'm not sure I can tell what's leaking.

This looking up from underneath the passenger side:
Click to view attachment

What most surprised me was how much oil was on the cooler:
Click to view attachment

Any advice on what to do short of tearing the whole thing apart and replacing all of the seals?

Thanks!

I think it's more than push rod seals. check the oil filler cover gasket. your best bet is to clean, then start the engine for a few minutes to spot the leaks. brake parts cleaner does an awesome job. Good luck!

seals are cheap. why not just reseal the whole thing while you have the engine out? plus, the more accessories you take off, the more you can clean. the easier it will to keep clean. and your hands and arms wont get so dirty every time you touch it.

Before you take anything apart, you may consider first removing the tins and then plugging all the ports and holes so the whole thing can be soaked in Simple Green (or your favorite cleaner) and pressure washed. That will make any seal removal/installation a lot easier.

On the 3/4 side, you also have leaks between the cylinders and the heads. That is what the oil 1/2 way down the push rods is from. When the engine is out is the perfect time to replace ALL the seals. It's the right thing to do.

I replaced my pushrod tube seals and oil cooler seals and something I noticed on my motor was the oil pump cover was not tight to proper torque specs. Hopefully my motor will run again in a few wks and I'll know if I got all my leaks. So check your oil pump cvr while your in there.

your gonna have to clean in stages.

First, don't use a pressure washer. Water will find its way in.

The oil on the cooler is coming from the cooler seals or the oil pressure sender. Pull the fan shroud and replace cooler seals, front crank seal, oil pump gasket, pressure sender, and pushrod seals. I would also pull the heads and replace the sealing rings if there is evidence of leaking. If the tranny is off, its a good time to check crank end play, and rear seal

Clean really well and then replace all the usual suspects mentioned above by Curt. Although I probably wouldn't pull the oil pump or the heads because you may find more things to fix while you're in there.

... and the easy one - the O-ring on the distributor shaft