BLACK OIL QUESTION

Muleskinner · Mar 4, 2006

I use Delo 400 15-40 in all of my Kubota engines, including my Dodge truck with a Cummins 5.9 diesel engine. I change my oil every 50 hours on the tractors. The oil in the tractors turns BLACK in less than an hour after changing the oil and filter. In the Cummins it takes about 1000 miles to turn the oil black.

Now I know all about the soot being trapped in the oil, Etc Etc. I just wonder why the Kubota engines turn the oil black so quick. I believe it's because the Cummins is a "Direct injection" engine, where the kubota uses an "Indirect injection" engine. My dealer's tech was unsure why the oil turns black so fast, but agreed the indirect injection may have something to do with it. It would be interesting to see if the oil in the new 2006 M series direct injection engine gets black as fast or stays cleaner longer.

What say you?

Egon · Mar 4, 2006

The oil in my Kubota turns black as soon as its changed.

On the Dodge Cummins the oil on the dipstick remains clean almost till it's time for an oil change. Course the oil comming out the drain is black.

Egon /forums/images/graemlins/grin.gif

ccsial · Mar 5, 2006

The oil on all 3 of my tractors turns black very fast. My Dodge Cummins never gets as black as the tractors.

JJT · Mar 5, 2006

In both of my Kubotas the oil takes at least 10 - 20 hours before it starts to turn dark. I'm running Rotella synthetic and change my oil annually, (80-100 hours).

Why not spend $10 and send a sample out for analysis? I bet at 50 hours your black oil has lots of life left in it. I use Oilguard for analysis. Before analysis I used to change my oil twice a year in the tractors and every 3000 miles in the cars. Now I'm annual on the Kubotas and 10,000 miles on the cars. Based on analysis I could easily go longer, but my current intervals are easy to remember.

Builder · Mar 5, 2006

Very interesting. So what you've found is that previous to testing, you were changing your oil much too soon/frequently?

We should all have such good information. The drain intervals seem to be increasing on diesel trucks.

_RaT_ · Mar 5, 2006

Good post John, I agree with you.

5030tinkerer · Mar 5, 2006

Has anyone tried Amsoil's new EaBP by-pass oil filter that supposedly filters out the soot? I am tempted to try on my next change. Have never used an Amsoil product, but am intrigued.

Av8r3400 · Mar 5, 2006

My VW diesels are the same as my Kubota. My old Chevy 6.2 was the same also. Oil goes black almost right away. My Cummins will stay "clean" much longer. I think it may have something to do with the "direct injection" on the Cummins. Maybe this just runs cleaner? Dunno.

Muleskinner · Mar 5, 2006

Well at least I know it's not just mine. Would be interested in hearing from anyone with the new M series direct injection engine after their first oil change.

cp1969 · Mar 5, 2006

</font><font color="blue" class="small">( My VW diesels are the same as my Kubota. My old Chevy 6.2 was the same also. Oil goes black almost right away. My Cummins will stay "clean" much longer. I think it may have something to do with the "direct injection" on the Cummins. Maybe this just runs cleaner? Dunno. )</font>

Unless you have old VW diesels, they are direct injection.