I am posting this for my brother, about his 96 2500 with 5 speed and 4.10 gears. It never fails with his truck while driving freeway speeds (75 mph), it will lose 1 to 1.5 gallons of oil in one trip of only about 100 miles, which is out of the breather tube and the dipstick tube. i can understand a little oil but not this much. The truck does not burn any oil, it has about 275,000 miles but runs like a champ. when driving the truck at 65 mph or less, it does not lose hardly any oil at all. Thanks for the help.

 

sounds like the same problem I have...bad blow by

Except mine takes about 700 or so miles to lose a gal, and mine does burn it as well

 

Mine does that too. Mine does not burn it though, just pushes it out the blowby tube. I even get a haze from the tube at idle.

It's annoying but truck runs good. I think mine was due to the clogged cat that I just resolved.

Joel

 

Well, I honestly think the only reason mine burns oil, is I have a system on it cummins sells that sends the blowby to the intake to burn. My blow by is so bad that the filter in this system that filters the oil residue out and lets if drain back to the pan just can't keep up, and a good bit of oil gets entrained and goes thru the intake.

My blowby when I last checked it was 3x normal, and that was 3 yrs ago, and had I not put this system on the engine, I could not drive it without leaving a big cloud of smoke whenver it stopped moving.

I mean literally, if I would stop at a light at night, there'd be so much smoke around me from the blow by, that it'd be hard to see to take off again if there was no wind to blow the smoke away....no kidding.

If I get on mine hard, it will blow so much oil out the disptick tube it looks like you poured a quart of oil on the OUTSIDE of the drivers side fender (it blows that hard that it makes it outside the engine compartment and between the hood & fender)

 

sounds like its time for a rebuild mine has 291,000 and i have a open to atmosphere tube and cant see even a haze and never loses oil. it will leave a drop once in awhile but nothin like that

 

I should have known when I got it from the blowby I saw then.

The PO ran a #0 plate he made in it, and I think that's what killed the rings from what he was saying it did while driving.

Mine only has 168k on it.......


How you like that #11 plate. They told me the #11 was not recommended for a 5 spd.

 

i love it it spools almost istantly it can get hot but i plan on adding a second turbo to the mix my milage increased when i slid it forward i am glad i got it

 

But why only at 70+mph. I can drive 60-65 all day and not lose a drop. I'm sure someone will say "It's the RPM's stupid." BUT I drive a lot of tight curvy roads here in the sticks and will often leave it in 4th gear and just wind it out between the curves, still no oil loss. Get on the interstate for 70+ and pukes out oil by the gallon.

 

High "blow by" can also be caused from a failed head gasket. Not often by they can fail on the edge next to the valve train valley and pressure up the crankcase. Easier fix than a bad set of rings or liner..

 

trying to get a leak down or compression check done to figure out what it is exaclty

 

Where is your boost at? Sounds kinda like the speed you start to carry a few pounds continuously, to me sounds like a cracked piston ring. I drove a dock truck with a ISB in it and i started to notice when i would run it hard for certain bursts of time, it would leak oil out the breather. Then one day pushing into a head wind foot on the floor for over an hour i got the job and the truck was completely covered with oil(not even any on the stick). Turned out to be a cracked ring(s). The higher cylinder pressure would cause it to leak down and pressurize the crank case and push all the oil out, but under light loads (maybe speeds) it would not leak or it would leak very little.

 

The 5.9 is notorious for losing oil at high engine rpm's. It is so bad that the marine applications come with owner warnings about continuous high speed operation.

What happens is the crankshaft windage whips the oil to a froth and then it blows out the road draft tube on the vehicle applications.

The best solution is to try different oils, like John Deere's Plus 50 15-40 or a good diesel rated synthetic and see if the problem goes away.

 

is there a theory as to why some eninges might do it...and others never seem to lose a drop through the tube?? i have heard quite a few members reference john deere oil...is there a reason it might perform differently?? vs

 

I don't think the synthetic oils aerate as easily.

This thread has made me think back through the progression of issues with my truck. I'm going to experiment with additional ventilation. If it works I'll post back with how/why details.

 

For the ADD members. IT WORKS!!!! You just need better breathing for the engine. For those who want more detail, read on.

I bought this truck when we were getting ready to move. i made lots of high speed interstate runs with and without the trailer. Never had an oil loss problem. After we got moved and settled in I started to fix various things on the truck. When I did the KDP/front seal I found my crank was heavily scored. Under the gun for time I cleaned it up a bit and threw the new seal in. Next day I lost a gallon of oil in 400 mi.. At the time I chalked it up to the front seal issue. Anytime I ran 70+ I could push a gallon in 100 mi.. Since I don't do a lot of 70+ in daily use it was quite a while before I got around to sleeving the crank and putting in another seal. When that didn't cure my oil consumption problems I started looking for other leaks but wasn't really finding anything to account for that sort of loss.

When this thread started it got me thinking back through the progression of events. Something I had forgotten about was my oil fill tube. When I did the KDP I found my tube was completely unscrewed, allowing oil to dribble down the front cover and make a mess when filling, but more importantly, providing extra ventilation, right where they moved the vent to on the 24v(maybe they were smarter than we thought). To test this theory I bought a breather cap for a 1 1/4" hole and screwed the rubber grommet into the threads on the fill tube. Running around local it seemed like it was working but hadn't really done more than 15-20 mi. runs at speed.

This weekend I ran 325 mi at 70+, a good test. Lost NO oil. Didn't have to refill every time I stopped, back of truck isn't covered in an oil film, couldn't be happier. Best part is no oil vapor out of the new breather trashing the engine compartment. Now that I know it works I'll probably pony up the cash for something better, like the Case breathers or maybe a closed system. I'd hate to have that breather come out and fall into the fan, although it seems to be staying put just fine for now.

Hope this info helps some of the rest of you with your oil loss problems.