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Oil in Fuel - Printable Version

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Oil in Fuel - Dustink1984 - 05-22-2019

Hello All,

Need some assistant I have 2004 International 9400i with a CM870 Cummins ISX motor. Vehicle had an engine oil leak at rear of head gasket. Removed Cylinder head, had head sent out to machine shop and had head inspect etc. Machine shop replaced Cam Bearings and did all normal pressure checks, cleaning etc. Got everything reinstalled, overhead set has been adjusted per spec. We are having an issue with the vehicle runs for aprox 30-35 minutes its getting small amounts of oil contamination in system, noticeably in the DAVCO. Have read all about the algae etc building up tanks. We actually have the engine running off a bucket of fuel directly from davco and same issue runs for about 30-35 minutes and produces oil. All the injector seals minus the oil seals in top of the injectors have been replaced, anyone have any insite on this. Vehicle does not smoke or misfire at all. Appreciate any help give :)


RE: Oil in Fuel - Waterloo - 05-22-2019

I'm going to take a guess and say that reman head is the issue... They are one time use, few if any reman heads make it very long on the these ISX motors.


RE: Oil in Fuel - Chamberpains - 05-22-2019

If you're getting small amounts of oil in your davco then you should have huge amounts in your fuel tanks. Shine a flashlight in there and see if it's in your tanks.

Are you sure it's oil and not asphaltene? This is a common black substance that you will always see in your davco filter. it's a byproduct of the fuel system in the ISX. No way to get around it except for to filter it out. Have you had it sent off to be tested? they'll be able to tell you if it's algae, asphaltene, oil, or even coolant.


RE: Oil in Fuel - Dustink1984 - 05-22-2019

The cylinder head is original head on the truck was only removed due to oil leak at back of cylinder head from the head gasket. We don't remember seeing the davco turning black prior. Yes the Fuel in the Tank is black as well, have not sent it off for a sample yet. But we have the truck running off a separate fuel source directly at the davco and davco was still turning black. Is this a normal issue then? I understand there is no way telling without a sample being done.


RE: Oil in Fuel - Rawze - 05-22-2019

(05-22-2019 )Dustink1984 Wrote:  The cylinder head is original head on the truck was only removed due to oil leak at back of cylinder head from the head gasket. We don't remember seeing the davco turning black prior. Yes the Fuel in the Tank is black as well, have not sent it off for a sample yet. But we have the truck running off a separate fuel source directly at the davco and davco was still turning black. Is this a normal issue then? I understand there is no way telling without a sample being done.

if the original head had more than 435k miles on it when removed, then was machined by a repair/head shop,..YOU WASTED YOUR MONEY! - take it off AND THROW IT AWAY!!!! --- ITS NO GOOD!

people always have to learn the hard way that those heads cannot be re-manned with any kind of long term reliability. its sad but follows a very consistent pattern of "I had the head re-manned,.. it made it 200k miles or so and now the head is junk again".


oil in fuel may or may not be a separate issue. it has been discussed many time on this forum in the past. This came up on a search.


ref: http://rawze.com/forums/showthread.php?tid=3558&pid=30747#pid30747
Quote:And then there is the all too familiar guesswork of ill-fated logic from an undereducated mechanic blaming anything "black" in the fuel system always on "combustion gas", oil, or "soot" , and all sorts of guess-work garbage.

--- FIRSRT AND FOREMOSRT!!! -- ALL ISX ENGINES -- ALL OF THEM!!! THE FUEL FILTER WILL ALWAYS TURN BLACK NO MATTER HOW GOOD THE INJECTORS AND FUEL SYSTEM IS!!!. PERIOD!

This is because MOST NEWER DIESEL ENGINES use rail and/or injection pressures that break down bio-diesel blends and cause a buildup in the fuel system called "ashpaltine". it is a normal process of the fuel system. Using a 10-micron Davco or fuel-water separator filter will keep it at bay and out of the tanks.

For ANY mechainc to look inside your fuel tanks and blame anything at all that is "black" or to look at your fuel filters or fuel components and say "must be combustion gasses or soot" is completely undereducated -- It is like saying "The car accident must have directly been caused by the skid-marks in the road and not the excessive speed,.. look, they lead right up to the car."


If you want to investigate what is actually in your fuel system, send off a fuel sample to a real lab instead of one of those over-night crap "color test" placebo's and see what is actually in your fuel.


-- I am not ranting at anyone directly here as much as I am pointing out the brainwashing and blindness that so many people get themselves caught up into. -- NEVER EVER guess --- Investigate and solve your problems properly. Stay away from mechanics that are blind, arrogant, too lazy to perform proper tests, and undereducated on these subjects.



RE: Oil in Fuel - Dustink1984 - 05-22-2019

Thanks for the Updated Guys, Nothing was wrong with head expect replacement of the cam bearings, the head had 350K on it. The fuel that was in the tank was already black So i'd assume this was already an issue before. We sent the Fuel out to be tested to see what comes of this. Appreciate your guys help.