odd Cummins oil-leak

[cadillackid]

Originally Posted by dredman

So now I am CONVINCED the "oil leak" is caused by pressure. It is extremely variable - yesterday just outside of Butte, I put 1/2 gallon in (<40 miles), after seeing a typical - big puddle/little puddle




But here is the kicker.....
After driving another 80 miles to Missoula, smaller to no hills, almost no oil loss(less than a quart) and two small drops(much like I Left Billings AND Buffalo with after repair)




So I really want to explore the pressure option, as the variable leak is baffling me.

So, Christopher, how did you resolve your Peugot leak?

unfortunately in my peugeot it was Very high amount of blow-by because I had broken one of the compression rings on 2 different cylinders.. the cylinders still fired.. thioyg hthe engine started up a tad rough on cold mornings... plus that car had baffles and a type of filter to try and curb the blow-by smoke... that filter would get blasted with oil and then cause even higher crankcase pressure which just blew oil out of any seal it could find..

the resolution for me was replacing that filter / baffle thingie with an updated version from a VW.. and then of course rebuilding the engine so I had good rings...

-Christopher

[family wagon]

Can you temporarily run with the oil filler cap removed? That should provide a much bigger crankcase vent path.. though perhaps there'll be a significant amount of oil mist exiting along with the blow-by gases. But would it be less oil exiting through there than is new (theorized to be) exiting through the breather or past the seals?

An oil analysis would reveal blow-by through contamination with fuel and/or soot wouldn't it? So long as it wasn't too diluted with fresh oil, that is.

[cadillackid]

does the cummins blowby tunbe not just point at the ground? on my IHC engine i have a tube that comes from the crankcase and just points at the ground... is the cummins recirculating the blowby into the valve cover?
-Christopher

[dredman]

Originally Posted by family wagon

Can you temporarily run with the oil filler cap removed? That should provide a much bigger crankcase vent path...

too much splash to do that.

[dredman]

Originally Posted by cadillackid

does the cummins blowby tunbe not just point at the ground? on my IHC engine i have a tube that comes from the crankcase and just points at the ground... is the cummins recirculating the blowby into the valve cover?
-Christopher

the blowby points towards the ground, I can catch oil.
My concern is blockage in any EGR apparatus, although I cant find any exit tub from the crankcase? I would really like to bypass that system, running around any valves or filters if I can, just cannot figure out where they are?

[cadillackid]

Originally Posted by dredman

the blowby points towards the ground, I can catch oil.
My concern is blockage in any EGR apparatus, although I cant find any exit tub from the crankcase? I would really like to bypass that system, running around any valves or filters if I can, just cannot figure out where they are?

I know PCV is often the cause of oil leaks in gasoline engines.. .. in older GMC engines it would often pop a weak point in a pan gasket.. the blow-by tube should handle that in a diesel

im not familiar with EGR in diesels.. however EGR shouldnt be putting pressure on the crankcase.. it should be exhaust manifold to air intake and not hit the crankcase.. if there is a crankcase recirculation system that sends crankcase gasses to the intake then that could be a source.. then I would think you woulkdnt havbe a blow-by tube then..

my Bus is too old to have an EGR system.. i just have a blow-by tube which i never see anything come out of.. at least not at idle or if I brake torque it a bit...

is it possible the engine is just worn enough you are making huge amounts of blow-by causing the high crankcase pressures? just curious if any of the shops have taken compression on the cylinders? like in my peugeot it still seem to run and drive and didnt have a skip or a miss even though i had busted rings..

-Christopher

[dredman]

Originally Posted by cadillackid

is it possible the engine is just worn enough you are making huge amounts of blow-by causing the high crankcase pressures? just curious if any of the shops have taken compression on the cylinders? like in my peugeot it still seem to run and drive and didnt have a skip or a miss even though i had busted rings..

-Christopher

I would think if I had that badly damaged engine that it would show SOME smoke, and I have NONE?

[cadillackid]

Originally Posted by dredman

I would think if I had that badly damaged engine that it would show SOME smoke, and I have NONE?

my peugeot didnt smoke... if you have worn compression rings but good oil rings you wont burn oil as the oil ring still sweeps the oil off the cylinder wall on the intake stroke so it doesnt end up in the cylinder to burn..

compression smoke would only be an issue perhaps on cold start and if the compression were low enough that cylnder was having trouble burning fuel..

I would think thoiugh that youd see some blow-by smoke from the tube at idle... on my peugeot I rember a pulsation of blow-by smoke from that tube at idle.. not alot but some.. since it was a pulsation in tiune wit hthe rhythm of the engine i surmised that it was an issue in one (then 2) cylinders and not engine wide... it smoked on startup a bit more than it had previously...

of course that was a little 4 cylinder car diesel vs a big truck engine like we are dealing with.. but it was a mechanical diesel with the Bosch fuel injection system..

you almost need a go pro on the front bumper pointed under the bus to see what the blow-by tube looks like when you hammer a heavy hill....

-Christopher

[2kool4skool]

Well Dred it's been almost a week....Wassup?

[dredman]

Originally Posted by 2kool4skool

Well Dred it's been almost a week....Wassup?

Sorry, been up in the woods (almost in Canada) enjoying life without Interwebs. Back in civilization today, headed back to Missoula. After close to 200 miles I have added less than a quart, think the takin-er-easy approach is working..... for now.



a little preview of what I have HAD to endure for the last few days....

[Tango]

It's tough work...but somebody's gotta' do it. Here's hoping the oil thing stays sane. Ride on.

[onenationundergoat]

Not sure how your engine is set up, but we had a major oil leak that we thought was coming out of the blowby tube, but it turned out our oil pressure pipe to the turbo had been chafing against some lines and had a pinhole in it. To find it we cleaned all the wet oil off the engine (it was all over the exhaust and oil pan next to the tube) and then ran it in place for a good long while to find out where a drip would spring up.

I don't remember what kinda bus you have but if it's wet sleeve and you need a rebuild it's honestly not too hard to do yourself if you have tools.

[dredman]

well I figured dragging this thing across CO Rockies might finish her off, and it is starting to look like that might be the case. Once I get her started she runs like a top, and pulls like a schoolbus. Even crawled across Vail Pass this afternoon - runs like normal?
This only happens when she is cold, otherwise she bumps right off?

Anything I can do to get her down the road a few more months? (2500 miles)
How long till she does not start?
Would ether help?

Headed towards Grand Junction to ask a diesel guy

Skip to 4 minutes to avoid MOST of the pain

https://www.youtube.com/watch?v=f9eirCYpdMI

[turf]

im not sure how the cummins does it, as i dont think there are glow plugs. but hard starting at altitude can be a sign of failed glow plugs. fuel isn't preheated enough to combust.......

hope that helps

[2kool4skool]

Originally Posted by turf

im not sure how the cummins does it, as i dont think there are glow plugs. but hard starting at altitude can be a sign of failed glow plugs. fuel isn't preheated enough to combust.......

hope that helps

They have a grid heater in the intake tract.

[dredman]

well it is good to know that it might be fixable. I have been high up (8,000+ feet) and it has been pretty chilly up here.

So would ether help start it?
Is there a way to check the heater?

[2kool4skool]

Dred, Cummins says NO ether!

There's a intake heater icon on the dash. When you start the engine do you wait until all the pre-start ritual* is complete? That gives the heater time to do it's thing, that is: key to run...wait*, then to start.

[dredman]

yes I wait, I even wait on subsequent attempts, and even cycle without starting

[Brad_SwiftFur]

Yeah, seems to me the preheater grid isn't doing its thing. Typically it's supposed to (1) turn switch to run (wait to start), (2) wait the few seconds for the heater to warm up, (3) turn starter. Ford 7.3's and others do much the same thing. My suggestion would be to see if the grid heater is getting voltage when it's cool. That'll help narrow it down.

[dredman]

Originally Posted by Brad_SwiftFur

My suggestion would be to see if the grid heater is getting voltage when it's cool. That'll help narrow it down.

Wonder why it had issues at noon tho? - Think it was close to 70 degrees?