If the oil is pouriing out of the breather tube in that kind of amounts, somethig is definitley pushing it out. It's possible a crack in the head could allow water to flow in and displace it, but you said your not loosing water or filling the crankcase with anything. I'd say a broke piston ring at the least, maybe even a hole in the top of a piston or cylinder wall. The higher compression gasses are definitley getting into the crank case.

I go with a compresion test from here. You could probably rent a gauge from a local auto parts store. You'd have to pull out the injectors, and maybe disable the fuel so it wouldn't allow it to start/pump fuel.

 

thanks i'll start there and try it first.......let ya know what i find

 

Seals on the vacuum pump wil cause the oil to pour out, but it sounds like you are confident that the oil is coming from the tube so it is probably not the vacuum pump...wow this is amazing.

It sounds like piston rings like charliez says. The truck won't smoke because it isn't burning oil, it is basically filling the crankcase with the expanding gasses from the ignition cycle. Basically the exhaust from a cylinder is blowing into your pan and out the breather tube and taking vast quantities of oil with it.

Did your power and mileage decrease before this started happening?

 

My biggest curiosity came when you said someone plugged the breather. That would tell me someone had this issue when they sold the truck. Why else would you plug it? You probably have't noticed any performance change or econonmy change because all you did was open the tube and it went to spilling. If this is true, I wouldn't be surprised to see a bad cylinder if it's been run for two years plus with an issue. Especially if it's a ring issue. Cylinder walls don't seem to get along with busted rings.

 

Its frightening to think that someone would just plug it! Where was the pressure going? It must have been blowing out the dipstick or something and getting worse over time....bummer.

 

You don't need the dealer for anything on the motor. Get everything from Cummins.
Have you done a compression test yet?

 

Cummins doesn't usually check engine wear with a compression test but rather by blowby pressure.
You need a blowby tool.
The Cummins blowby orifice tool is simply a tee with one .221" (15/64-in) outlet. Connect one end of the tee to the end of the blowby tube. Put a manometer on last tee outlet. That is your blowby tool. They sell them at the Cummins, but I have made my own plenty of times, less than $10. A simple manometer can be made by looping into a 'U' 6 feet of clear tubing with water in it half way. Measure how high the water level rises with a tape measure, multiply it by 2, convert it to LPMs.

Rough conversion is 1"= 27 lpm, add 3 lpm for each one inch (1/2'' of rise in the tube) of water

The reason for multiplying by 2 is that inches of water equals the water rise in the open end of the tube plus the inches the water is pushed down on the engine side of the water tube. For simplicity my numbers below are the measurement of rise only.


Cummins new 5.9 engine numbers are:
63 liters per minute(2.5" water rise) @ 2200rpm,
76 L/Min (3.5" rise) @ 2500rpm
85 L/Min (4.5" rise) @ 2800rpm.

Worn engine that needs rebuilding are roughly double i.e.
126 L/Min(10.5"rise) @ 2200rpm
152 L/Min(14.5"rise) @ 2500rpm
170 L/Min(17"rise) @ 2800 rpm

Beside indicating a compression problem the valves could also be out of adjustment.

Another way (mine), same idea, is to block the blowby tube with a 1/2'' pipe nipple with a cap that has a 15/64 hole drilled in it. Use 3/8'' id looped clear tubing with water in it slipped over the oil dipstick tube. Other tubing end remains open. Use a sharp tipped felt marker to mark the water level with the engine off, have a helper start an already warmed up engine and run the rpms up to 2.2, 2.5 & 2.8k rpms. Mark each water level with the pen, measure the distance from engine off mark then multiply each by 2.

This is all very simple to do, just hard to explain with words.
__________________

 

You say the breather tube was stopped-up when you got it . . . .


The oil that goes to the head drains back to the oil pan by way of the lifter valley (V8 jargon). The breather tube is simply mounted on, and vents through the cover of the lifter valley.

--> If the breather tube was stopped-up, what's to say the oil drains in the lifter valley aren't plugged with the same poopoo that plugged the breather tube?


It sounds like that when at a higher RPM, the volume of oil sent to the head out-runs the drain back capacity. Oil is stacking up in the lifter valley and ultimately coming out the tube.


IMO, the thought of blow-by being an issue is muddied-up by the fact that you say it still occurs when in neutral and reving the engine. There's next to no boost in that setting.


Pull the lifter valley cover and make sure the drain holes aren't restricted.


Hope this helps.

 

They do.

Just a thought though...

 

Not quite.
There is filter screen mounted inside that when clogged stops up the blowby.
Most common reason for it to clog is the use of gasser motor oil. Diesel motor oil is designed to hold soot, gasser isn't. Using gasser oil causes sludge deposits all over the engine including the blowby screen.
If the previous owner used gasser oil extensivly it could be the whole problem, a constipated engine.

 

truck is still at mechanic...told him to leave it alone.. have a friend that wants to check it out himself he works on diesel engines. will pick up the truck on friday... let everyone know more monday,,, thanks for all the suggestions its greatly appriciated!!!

 

A compression test will tell you in a flash if you had something bad in a cylinder. The pressure would be lower if it's bypassing a ring. If you know you have one with lower pressure, you would know the head at least needed to come off, and once that's off, I think he's going to be able to see the issue. A broke ring that's been run for two years should leave a mark on the cylinder wall.

Also, if I read right, the tube was plugged by an object that someone stuck in there, not by gunk.

 

I understand that.

I suppose the real question might be ~ Why is oil stacking up in the lifter valley to be blown out in the first place?

I propose the same trash that's plugging the breather tube assembly is plugging the valley drain. When the engine speeds up (oil pump speeds up) the volume of oil sent to the head and valve train is more than the drain system can flow due to blockage. Under slower engine speed conditions, there's less oil volume, and the drain(s) can handle it.

Pull the side cover and have a peek.

 

. . . . . .

 

ojk.. so here is whats new... the mechanic said the fuel pump went out, had to change that then he keeps insisting the rings or piston are shot. wants us to sell it now... picked it up yesterday runs like a tractor now. my friend came by and said that the fuel systems just needs to be set. the rpms have to be really high (3000 or better) before the oil comes out. no blowby anywhere. someone suggested that the head gasket may be blown but wouldn't there be oil and water mixed? gonna start with the side cover and go from there. thanks for all the info and i'll let ya know!!!