Engine/Transmission (1998.5 - 2002) 98.5 Using oil.Where is it going?

[99problems]

I have a 98. 5 cummins that is using a ton of oil. No white or blue smoke. Turbo replaced. Motor was recently rebuilt from the bottom up (new bearings, rings, block decked, head shaved, pistons cut). No leaks under the truck. Where is the oil going? Almost a gallon per 300 miles. Other days it will not burn any... PLEASE HELP!

 

[JLandry]

When you say no leaks under the truck, do you mean no drips at all when parked? Any sign of an oily film on the front of the engine or suspension?



I'm wondering if there isn't a massive amount of blow-by from the crankcase breather tube only under load.



An oil leak detection kit might help you figure out where the oil is escaping... it has to be coming out somewhere.



John L.

 

[99problems]

I have a few drops from the rear main... Nothing out of the breather tube, no oil residue, and no blow by... I'm out of options. The only thing I can figure is that the piston rings havent seated since the rebuild because it's only been a few thousand miles. However if the rings were leaking I would have white or blue smoke... . I honestly have no idea what is going on.

 

[99problems]

How can I tell the amount of blow by there is when the truck is under load? If that were the case would there be a lot of oil coming out of the tube?

 

[JLandry]

How can I tell the amount of blow by there is when the truck is under load? If that were the case would there be a lot of oil coming out of the tube?

Depending on where the tube exits on your truck's engine, with that much oil consumption, you should have an oily film somewhere.



How's the transmission fluid and coolant looking?



John L.

 

[99problems]

There's no oil under the truck. I figured it was the turbo or the rings. New turbo and still happening... Nobody can figure this out. And the tube come right out of the front of the engine right behind the fan.

 

[99problems]

When I say no oil I mean nothing anywhere on the underside of the truck.

 

[JMetzger]

I would think if you had excessive blow by you would smell oil in the truck or standing by it.

 

[NIsaacs]

If it is not leaking, it is burning the oil. A turbo charged engine will not show blue smoke unless the oil usage is really, really bad.



Nick

 

[Sticks]

You'd be able to smell it though.

I take it your coolant is not getting contaminated? At the rate you are talking, you'd be running nothing but oil for coolant now.

I'm a little perplexed as to your estimated consumption (some days a gallon per 300 miles, other days none) How many miles on this rebuild?

Auto or manual trans? When you say the rear main was leaking a few drops, how could you tell?

I'd think if you were burning it, you would see the evidence on the exhaust ports if you were to pull the exhaust manifold, especially if this is a fresh rebuild and the head was properly cleaned.

Piston rings, valve stem seal, might even be getting into your fuel on the return side if the head was cracked (pull your fuel filter).

 

[99problems]

Its a 5 speed. I took the truck 300 miles on a trip and burned nearly a gallon of oil. Then I drove about six hundred miles just back and forth to work for a couple weeks and no oil was used. If I am getting blow by when its under load, would I have oil coming out of the breather tube? The only thing I can figure is something may be up with the rings or the valve stem seals. Other than that I am out of options. I have a FASS too and recently changed the filter. No issues there. Im just as lost as everyone I talk to about this. And the coolant is holding fine and completely clean. The oil never gave me an issue prior to the rebuild. The reason I had the motor redone was because the corner of the block was slightly warped and the head gasket kept leaking. Now I have no coolant issues, just this oil issue.

 

[Dieseldemon]

Has it happened only once on your 300 mile trip or is it still using oil?

 

[99problems]

Its hit or miss. I can drive it for a few days and check it and it will be fine. Other times I check it and it used some.

 

[Dieseldemon]

Try leaving it down a little and see if it continues to go down or stabilizes at a lower level I had a cust that had the same problem but it stabilized at a lower level I am talking a half quart lower.

 

[99problems]

I pressure washed the under side of the truck and it looks like the breather tube is where the oil is coming from... Any idea on what is causing this?

 

[DavidC]

If it is coming from the breather tube that is a sign of the rings not seated or broken pressurizing the crank case . A compression check or leak down test would tell what cylinder or cylinders are affected.

 

[JWiegel]

Do you still have the bottle on the tube, and if it is excessive blow by first place I would look is at the valves causing high crank case pressure and blowing out the blow by tube.

 

[fest3er]

Remove the oil filler cap (the one with '710' on it) and zip-tie a piece of fabric over it. If oil consumption goes down, you have a lot of blow-by. When the crankcase gets pressurized, the oil from the upper end can't drain back to the pan and finds other ways out.

My '98 was using a qt. every 300-500 miles about 8 years ago. I pulled the 710 cap off and installed some PVC plumbing to keep the crankcase open. Oil consumption immediately dropped to a qt. every 2500 miles or more and has stayed there. The plumbing is still there.

 

[99problems]

Thanks guys... Apparently the company that rebuilt my motor didn't use the rings that cummins calls for. I think you are right about the blow by... We held it at a high rpm for about 5 minutes and so much oil built up that it blew the valve cover gasket. Calling tomorrow and telling them they need to rebuild this thing the right way.

 

[Dieseldemon]

The best way to find out what is going on is to do compression test that will give you the full story If it was just overhauled it should be in the neighborhood of 500 psi you said the pistons were cut where and how much and why?