Cummins ISL 400 oil consumption

[swatty]

Have a 2005 Horizon with ISL 400 @60,000 miles.  Stated using 1 gallon oil every 300 miles returning from Alaska.  In the shop now but they cant seem to find reason without tearing down engine.  Any ideas on a Diagnostics?

 

[Ghostman]

That's quite a bit of oil for a short distance. It is either leaking out or motor or burning it up. If it's not leaking or can't smell a oil smell. Sometimes I have seen leaks that don't make it to the ground but it gets burnt by exhaust or someother part of motor. I doubt that is your case with that much. They would have seen it anyway.

If it's the motor it is probably either rings or turbo. The turbo seals can go out and you will burn the oil or go into the intercooler. If it is your rings. I am suspect here if it is running ok. They should be able to do a compression check on the cylinders. Also if the rings are that bad it should have quite a bit if blow by out the oil fill or dipstick. We had one that a cylinder failed and it was shooting oil out of the dipstick.

 

[WILDEBILL308]

Have a 2005 Horizon with ISL 400 @60,000 miles.  Stated using 1 gallon oil every 300 miles returning from Alaska.  In the shop now but they cant seem to find reason without tearing down engine.  Any ideas on a Diagnostics?

Welcome to the forum. Has the dealer checked compression and blowby?
Keep us informed.
Bill

 

[Gary RV_Wizard]

That vintage of engine can blow a lot of oil out the "slobber tube" (crankcase vent) as well as burning it or leaking it. Any signs of oil film on the back of the coach or the towed car? 

What about the exhaust color?  Is it clear, gray-ish or black?  Smoke at start-up, or all the time?

Have you changed the oil filter since this started?  A clogged oil filter can have strange side-effects, so an simple oil & filter change might be a first step.  My ISL began blowing the oil filler cap off and losing oil from it, but an oil & filter change solved that problem.

Any sign of oil in the radiator coolant?  I would not be in a hurry to tear it down unless there is oil in the radiator.

Last, did this perhaps start after an oil change? Overfilling can cause an ISL to literally squirt oil out until it gets happy with the level.  Mine never liked to be "full" per the dipstick, nor could I ever use the full 24 quarts the manual called for. It was happy at about 22 qts, which was just at the Add line on the dipstick.

 

[darsben]

Are you at an RV dealer or a diesel repair shop.

 

[Jubilee]

In my experience, a sudden drastic increase in oil consumption in a cat or cummins has always been related  to the crankcase ventilation system. I would think all diesel shops would be aware of this, but I?ve seen it missed. Once had a cat shop want to overhaul one of my engines when all it needed was a crankcase filter cleaning.

 

[kdbgoat]

In the shop now but they cant seem to find reason without tearing down engine.  Any ideas.....

Yeah, find a real diesel shop. Not trying to be blunt, but whatever shop you're in now doesn't have a clue about engines. I wouldn't bother to take a lawn mower to them either.

https://salesandservice.cummins.com/locations

 

[swatty]

Its at a cummins shop now. 

 

[kdbgoat]

A shop shouldn't have to tear down an engine to figure out what is wrong with it, quite the opposite, they should be able to do a diagnosis to see if it needs to be torn down. I would still go to another shop. jubileee gave good advice. Wildebill and Gary asked some questions that need to be answered in order for them and others here to give you much more help.

 

[swatty]

To answer a couple of the questions.  There was visible blue/black smoke when letting off accelerator, then accelerating, or when going slow thru town, etc.  The shop has determined the turbo is not the cause, nor the ventilation filter.  Removed the exhaust manifold (needed gasket anyway) and found cylinders dry.  Still looking for cause.  This is no shade tree shop either. 

 

[WILDEBILL308]

To answer a couple of the questions.  There was visible blue/black smoke when letting off accelerator, then accelerating, or when going slow thru town, etc.  The shop has determined the turbo is not the cause, nor the ventilation filter.  Removed the exhaust manifold (needed gasket anyway) and found cylinders dry.  Still looking for cause.  This is no shade tree shop either.

Have you thoroughly checked the intake/air filter for leaks? Sounds like your engine is "dusted" Hope not. Have you pulled an oil sample?
Bill