I just finished rebuilding my 72 1.7lL and had an elusive oil leak. It would show up on the alternator, crossmember that holds the engine and the shift rod. I have a car lift and was able to get good observation of the area but still could not find the leak. It would not show up on idling the engine but if I took it out and drove it it would leak like a sieve. This is a picture of the block when I rebuilt it and it shows where it was coming from. Just like "where's Waldo" who can find the leak? Hint: it's part of the block on the drivers side.

Click to view attachment

Dip stick tube.

Threaded hole for the thermostat pulley bolt

I may have left the pulley off my bus motor at one point.

Def thermostat pulley bolt

All of the above

Oil pump, Taco plate cover, front main seal

Tons of people have made the same mistake with the pulley

Oil galley plug ?

Ray do you concur ?

The pulley bolt hole goes all the way through into the case.

Seen it many times on "performance" rebuilds where some misguided soul thought that removing the cooling flaps would somehow make the engine run cooler.

The “2nd” oil pressure relief valve?

I'm doubling down on dip stick tube.

I agree with all the folks who said the pulley bolt hole. Especially since it only showed up while driving, when the oil is sloshing around.

--DD

Pissed me off when I figured it out.

(I installed Tangerine's remote oil cooler which removes the flapper system).

Edit: still pisses me off thinking about it later.

This guy....as others have said. Fan pulley bolt. Click to view attachment

Probably not the only oil leak. Your engine is upside down. Oil is going everywhere.