A simple question if I may.

Isn't the main reason for the oil contamination the diesel getting into the crankcase? This is my first diesel and was quiet surprised when I looked at the dipstick oil (Black) at only 3500 miles. The service manager said it was normal.

 

Oil has always turned black in diesel engines, egr or no egr.

On my '15 I have noticed that I get a regen at 500 mi., and usually I'm at 90% or 95%. Then the next regen will be a short one, usually 15-17mi. and takes it down to 40%-45%. So every other regen takes it down to 20% and lasts approx. 25 mi.
Other model years may be different, but the programming seems to recognize a regen at 500 mi. if dpf is full or not.

When I get the short regen it will usually go off again at 425 mi. when it will be full 100%. I do reset my trip 2 every time a regen begins to keep track.

I do use 10w-30 year around and sample at every oil change while waiting for the message "oil change required". Every sample has come back excellent with zero fuel contamination.

My oil of choice is John Deere Plus 50 II 10w-30, which is still CJ-4.

 

I can't speak for the oil being black prior to EGR - bottom line is that:

*) Unburnt carbon particulates and other crap is getting into your oil by the EGR system

*) Diesel fuel is getting into your oil by the fuel that is dumped into your cylinders during a regen cycle slipping past the piston rings


I did read something interesting the other day - the egr systems in the earlier powerstrokes dumped a higher percentage of exhaust into the intake stroke to, as mentioned above reduce how much heat the combustion stroke generated. This was done to reduce NOx emissions. The EPA wanted NOx levels even lower than the dpf system produced, it forced the engineers to come up with something else to further reduce NOx - the DEF system. What the engineers found out was that the DEF system was quite a bit more efficient at reducing NOx than originally thought, this enabled them to reduce percentage of exhaust that was added to the intake mixture thus raising the temperature of the combustion stroke resulting in more efficiently burning the fuel. By more efficiently burning the fuel it reduces unburnt carbon particles which get trapped by the dpf. Reducing unburnt carbon particles in the dpf results in a reduction of regens thus reducing the number of times fuel is dumped into the exhaust stroke. Reducing how often fuel is dumped into the exhaust stroke reduces how much slips by and gets into the oil. The tangled web we weave.

 

I have a large fleet of f-350s with extremely high fuel dilution some trucks are brand new on there first and second services at 5k and some have 100k. 8-10% fuel in oil. However I have cab and chassis f-550 that can't get out of there own way that have never been over 3%.

 

Having studied this for a while including the 6.7 and the 6.4 my first thought is that you changed your fuel source. Ran a few tanks or an auxiliary tank of bio especially B20. Many say they don't always get dilution from bio but I think I do. I am sure I did in the 6.4. The EPA published a study and admitted that all DPF equipped diesels would experience some level of dilution. If you look back around 2010 or 11 on my posts you can find the study or the link to it.

The other symptom I find is that hard work, in my case heavy towing will reduce the dilution. That makes sense in that hotter oil temps will boil out some or all of the dilution. So, on the flip side if you normally work the truck hard but during this test period did not, then that would account for a change.

I've pretty much quit worrying about it as I've experienced no ill effects from it. I once thought it was a problem but I now think it's just a characteristic of DPF technology and Bio-diesel fuel and I see no way short of a political revolution to change it.

 

I quite worrying as well. Here is one of my 6.4 and one of my 6.7. I have not done an OA since.

 

Scott, did the two oil reports use a different viscosity?

 

No, I was running M/C Dino 15-40wt in both.