I’m having trouble identifying the source of this oil leak. From the top, poking around engine bay, the engine is quite dry.

The photos below are after a couple years of not cleaning underneath. I did degrease everything thoroughly and the first part that shows oil is that black plastic piece that sits between the oil pan and transmission pan. Oil runs down one of the ribs on that plastic and drips.

Everything else I believe is from the spreading as you drive.

It’s a small enough leak I never have to add oil, just enough to make a mess.

What is my next step? Anything easy to check or try to tighten? Or is this a rear main?

All original 1978 Olds 350 with 112k.

Thank you!
Brian

 

I had a bad rear main seal in my 455 and the best way to determine it was ,to clean everything down good and use the dye and a blacklight pen.i zeroed right in on it after a short ride and got it up on jack stands to look at it . You may want to remove the trans dust cover for better viewing.. some of that could be seepage from the oil pan gasket but ive never had much luck tightening the pan bolts.

 

As mentioned pull the black plastic flex plate cover, then look up closely where the crankshaft exits just forward of the flange that the flex plate attaches. If the crank is dry where it exits the block the rear main is ok. If it is wet...

 

People go to great lengths spending inordinate amounts of time chasing leaks having never used fluorescent dye to locate a leak. Hell Stevie Wonder could find that leak using dye.

 

Had time to look at this today.

Removed black plastic flex plate cover. Surprisingly - it was dry inside.

On closer inspection it seems the pan gasket is the culprit right in the center. Right where it’s very tough to reach the bolts.

I have a ratcheting closed end wrench that was able to reach, but couldn’t get much leverage. Turned slightly. The other bolts I snugged using a torque wrench set to about 10 lb Ft per service manual. Maybe I went very slightly over 10. Every single bolt turned at least a tiny bit so we will see if this helps.

With how little I drive the car, it might take a few weeks before I know if this was successful or not. I’ll come back and update.

Thanks everyone!