871 oil mixing with fuel

[joed2323]

How's it going guys... I got a buddy that has a 09 Kenworth with the Cummins motor. It has roughly 274046 miles and 18786 hours on the motor. This truck works in the oil fields and has lots of idle/pto time

His primary fuel filter is basically black, you can shine a light into the fuel tank and can not see the bottom of the tank, it definitely looks like oil is getting into the fuel system... And ideas how and what could be the cause? He removed the primary filter and drained the fuel into a oil pan, and can see plain as day that their was quite a bit oil in the catch pan

It is also has been burning some oil as well, he said roughly a quart a week give or take some...
The truck definitely likes to "roll coal" when it's been idling for some time, once you get going through the gears she does leave a grayish/black cloud of smoke pretty much anytime he goes to accelerate through the gears. Seems to smoke at random also

Apparently he recently changed out the dpf as well, thinking it would cut down on his smoke with no luck....

He is currently thinking to do a inframe before it's too late. What are your thoughts on this? I'm sure this is a common issue with these motors and with the amount of hours on this motor.

Could it be as simple as an injector o-ring leaking and mixing oil into the fuel return? Or possibly the high pressure fuel pump mixing with oil?

It was recently at Kenworth for ECM updates and the dpf, and had them check it over for the smoking issue and they said their was nothing wrong with the motor. It also had a tune-up a few months ago
Thanks guys

[Nilao]

This could be black algae. If you cut the filter open and feel the element it will be slimy if it is algae. It's hard to get oil into the fuel system as they are always under higher fuel pressure than oil pressure. I would definitely check it for algae though. It can ruin injectors and pumps.

[joed2323]

It doesn't/didn't feel slimy. It looked more like engine oil basically...
I guess it wouldn't hurt to treat the fuel with algae killer

[hhow55]

I believe what you see is asphaltene
Cummins has a product called asphaltene conditioner

[kmk]

Oil system runs at lower pressure than fuel. Algae or asphaltene would clog fuel filters, you might be looking at combustion gasses. Bad head possibly. Does he lose prime? Just a thought.

[Rawze]

Stop guessing, get a sample, send it to a lab and have it tested. That would be my first step if I had a fuel contaminant.

#1 on old engines is asphaltene buildup.

#2 is Algea in the fuel.

#3 something someone may have dumped into the tank.

It would be fairly rare and difficult to get oil (or even soot) in the fuel system. Algea can damage and destroy fuel system components. Nothing to play with, so finding out what it is via a quality lab that can test for all of those things should be first priority.

In the mean time, ensure you are not getting excess crank case pressure buildup or excess blo-by to cause it. One place to look is how new the crank case filter is. a lot of guys drill out the crank case filter to prevent any buildup, as it is bad for the engine and turbocharger too...

This is the maint. free one you can buy...
http://rawze.com/forums/showthread.php?t...50#pid8950

or if you want to drill it out yourself....
http://rawze.com/forums/showthread.php?t...376#pid376

an explanation...
http://rawze.com/forums/showthread.php?t...22#pid9322

[joed2323]

The crankcase breather does have the maintenance free one installed, so that rules that out.

I guess the smart thing to do would be to test the fuel like rawze suggests.

Let's just say the fuel is contaminated with algea or asphaltene buildup, would this result in high smoke output due to long term exposure? I guess if it contaminated the fuel system(fuel injectors) it would tend to smoke.

Kenworth swears up and down that it ran numerous fuel system tests and everything checked out OK, their words were (runs great)

I will have my buddy send in a fuel sample analysis and I guess start their first, and move down the line...

[Brock]

Where are you located? Canadian oilfields or states?

Never heard of anyone I know having algae issues up north.

[Waterloo]

My very first thought was Algae... I worked in the oil patch up in ND for a few years, and can tell you the fuel up there was expensive and crap. Most fuel was stored in above ground tanks, and not well maintained from my experience. Water from condensation was normal, but some outfits let it get out of hand, frozen fueling hoses were normal at a few places I fueled, and a real bitch in the winter. I can only imagine that more than a few of those tanks are infested with the algae and other forms of nastiness. Have the fuel tested like Rawze stated, but I would bet it is algae. If it is, time to stock up on the biocide and plan on treating at every fill up to keep it at bay, after the system is thoroughly cleaned out of the nasty critters.