odd Cummins oil-leak

[dredman]

so right now, the leak I have had for a few weeks, appears NOT to be coming from the front main sea as I feared, but appears to be dripping directly out of this hose, which I have been unable to determine, WHAT it is, or how to fix the leak. Any help with direction or where to look would be appreciated

A good picture of similar engine (not mine)

note arrow at bottom-right

[Skoolydoo]

Is the bottom of the hose open or connected? Looks like a blow by hose.

[dredman]

The hose is open, pointed to the ground. If it is a blowby, it is blowing a quart every 200 miles

[Skoolydoo]

Sure shouldn't be that much, that disc where the hose is connected at the top, does it come off? Is there a filter inside..I would think there is, like one of those kitchen sink scrubber things, if that is real dirty it could cause pressure to build up..but the underlying cause would be why so much oil is getting to that area.
Where does that other pipe connect to?

[one_eyed_jack]

That my friend is your cranckcase ventilation hose and if you are for sure loosing that much oil all from that hose then Im terribly afraid that your engine is in poor condition (bad rings or valve stem seals) or your oil level is too high. If it is your oil level being too high then why is it that way? Did someone overfill it at service or is fuel getting into the lube oil. Fuel can get past a bad injectionpump driveshaft seal on some engines but not sure about the 5.9.
Maybe someone else more familiar with the inner workings of this one will chime in here.
I do hope for your sake its something simpler but from here it does not look good.
Another thought is the possibility of a plugged drainback hole/passage under the front cover there, but I believe that's pretty wide-open back down to the sump in that area.
Cheers and best of luck with that.
One_Eyed_Jack

[one_eyed_jack]

I should elaborate on my comment about your engine possibly being in bad condition. What I meant was that if it realy is pushing as much oil as you say out that vent tube, it's likely compression pressure blowing past worn or broken rings or exhaust pressure blowing past the valve stems. Either one will cause excess crankcase pressure and push oil out the vent.

[Booyah45828]

That is the crankcase vent. The rubber hose can come off and that circular thing should unscrew counter clockwise with a filter wrench. That circular thing will have stainless steel mesh inside in order to catch and condense any oil vapor out of the blow by. Are you catching a quart every 200 miles or are you noticing that it's a quart low every 200 miles? Have you ever done an oil analysis? Sometimes those will show that you have excess fuel and/or hydrocarbons in the oil indicating excessive blow by caused by worn rings. With the engine running, how much air is being pushed out of the hose?

[dredman]

wow, thanks for all the great responses, no overfill since I have had it. The bus has been leaking for a couple thousand miles, before that - not a drop. Hoping I can do some diagnostics this afternoon. Other than removing the cap/filter mesh, is there anything else I can do or inspect while in there?

[turf]

watching this thread....

my bus probably does the same.

its never left a drop of oil in its parking spot, but the pan is "wet" with oil.

never understood why.

[one_eyed_jack]

As Booyah suggested check to see how much air/vapor is coming from that tube when engine is warm and idling. There is no actual test that I am aware of to determine, how much is too much, it's basicly a visual, learned thing that's acquired through years of experience operating or wrenching on engines. If you are unsure get a mechanic to have a boo.
Then like he said, oil analysis then compression check would be where I'd go.
Good luck:
One_Eyed_Jack

[one_eyed_jack]

Oh and dred, please keep us all updated on the outcome. And just out of curiosity how many miles on this engine?

[dredman]

Originally Posted by one_eyed_jack

Oh and dred, please keep us all updated on the outcome. And just out of curiosity how many miles on this engine?

Will document

160k not a hint of smoke

[one_eyed_jack]

Yes turf it is quite common on this era diesel engines to have these road-draft vent tubes which will expell more and more oil as the engine wears and piston/ring clearances get greater. Cylinder walls get glazed too, so compression pressure gets past the rings into the crankcase, soòo, that pressure, has to go somewhere and as this flow increases it carries more and more vapor and droplets with it.
For those of you who are not familiar with these engines and may only have experience with passenger vehicles, you may or may not know that this blow-by is handled in a different way. Since the late 50's early 60's this 8blow-by is re-circulated and drawn back into the intake manifold to be re-burned. So although your grocery-getter may have just as much blow-by (or maybe even more if it's a high-miler) as your, new-to-you, bus, you wont see it cause it's getting sucked-in & re-burned. Older (pre-sixties) cars and light trucks all used to have these open, road-draft crankcase vents and they were always marking-their-territory with varying sized drops (depending on their age/milage) of oil.
Hope this helps to relieve some of the mystery for you.
CHEERS ALL:
One_Eyed_Jack
P.S. One drop of oil splattered all over your under-carriage always looks like a Lot more.

[Skoolydoo]

You covered that very well.

[Booyah45828]

Dred, there is nothing to really see by pulling that filter off. There are no baffles behind it or really anything to inspect. It's just odd that it went from nothing to a quart every 200 miles, all the while it's not down on power, misfiring, or blowing smoke. A quick way to test if you have excessive blow by is to remove the oil fill cap in the valve cover while the engine is running at idle. If you have a bunch of airflow out the hole then it's ominous. Here is a video

https://www.youtube.com/watch?v=Ow6nDG1QHgo

.

Just out of curiousity, what oil do you run? and do you know what oil the district happened to run?

[dredman]

I want to post the video, get some responses from it, then discuss further

for reference

https://www.youtube.com/watch?v=9NzZeVvrFX4

[dredman]

from the filler cap

https://www.youtube.com/watch?v=1m0bcN66laU

[turf]

after seeing your videos and starting up my bus and locating the blow by tube, i think my oil leak is elsewhere.

i have a bit of air coming out of both the tube and the filler cap. but my leak is further in front of the location of the blow by tube.

good luck with it!

[Booyah45828]

It's not a new one by any means, but it doesn't look that bad imo, not quart/200 miles territory by any means. You got me baffled by it. You never mentioned what oil you run?

[dredman]

15/40 is spec'ed, been running that for 5 months, 6k miles or so
I am with you, does not seem bad at all, at least from the "Cummins blow by" videos I have been watching. I think it is something else