What's an oil exhaust ducting?

Oil drain tube. Probably not leaking there. More probably a bad valve cover gasket letting oil run there.

 

Brian,

how much work is it to replace a bad valve cover gasket ?? Is it very $ ??
I believe I have one too which is leaking a little. Need to get it fixed soon.....
Thanks.

 

Wait until you need a clutch or major service. It is a PIA.

 

Oil does not flow uphill. Your leak is above it.

 

Occasionally it does. I've had instances on my cars where an oil drip was getting blown upwards by engine bay airflow. Makes it more exciting to find the problem.

But that does look like the leak is coming from above the tube. It builds up on the tube, and then drips off. With oil constantly pooled against the VC gasket, it will come out very slowly even if the gasket looks fine.

 

It did last time he rolled his car

Oh, I guess it was down then too.

 

Really hard to tell from the pic where it might be coming from. It could still be an area above, if it's dripping of a downward pointing edge instead of flowing down the side of the head.

 

Looking at the pic it could very likely be the lower o ring is bad, allowing the crankcase pressure to blow oil up the outside of the tube. The oil/dirt pattern reminds me of the crud accumulated from a draft tube.

 

Crankcase pressure? Nope, not on one of those. They have crankcase vacuum.

 

I don't think that's the case here. I'd think there's little to no air pressure there, and it would hamper oil drainage.

 

If you run an engine with the oil cap off, you can feel the crankcase air pulses as the pistons move up and down. There's no real flow, but the air moves back and forth rapidly. Any oil mist in suspension with the air then has the opportunity to make a mess anywhere it contacts.

 

Have you ever studied the crankcase breathing characteristics of a drysump motor? The oil pump suctions out twice as much as it pumps in causing a vacuum in the crankcase. That plus the various vacuum lines attached to the intake pretty much assure an absence of crankcase pressure. If there is no air there is no energy wasted in the pistons pushing it up and down.

 

Brian,

I took few pictures of my small oil leak over the weekend. I circled with red were the oil
drips from. It drips below that nut and then down into the belly pan. What cover is that ??
Bad seal under that cover ??? Thanks.
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End cover gasket leaks are very common on 360. The oil pools behind it. Very easy fix.

 

Thanks Brian.

 

Robin,
All this work to replace one missing gasket? Damn...

 

I suppose the good news is you found the problem and took care of it.