Oil & Fuel off road diesel cause dirty oil?

   / off road diesel cause dirty oil? #1  

twodogs

Silver Member
Joined
Jan 6, 2005
Messages
162
Location
Pittsburgh, PA
Tractor
Kubota B7800
I just changed my oil again on my b7800 as I was approaching 200 hours. I change it every 50 hours. I use off road diesel. The oil seemed quite black to me. Is it from using off road, or is it from comparing it to the oil I am used to changing in cars? Am I doing any damage by running the off road diesel?
 
   / off road diesel cause dirty oil? #2  
Only difference between on-road and off-road diesel is the dye placed in the off-road type so the Po-po can fine you if you're running the stuff in an on-road vehicle. Off-road is cheaper since you're not paying certain taxes that you would at a "normal" pump.

Though I have never personally changed diesel oil (yes, I'm a wuss pansy that gives it to my dealer to work on), it would make sense that it is blacker than a gas engine. Diesel is, by it's very nature, dirtier fuel that does not burn nearly as clean as gasoline. The soot left on the sides of the cylinder after EVERY combustion event makes it's way into the oil by way of the rings, I would figure.

Should still be pleanty slippery, though. You can tell the difference between a "dirty" oil and a "broken" oil.
 
   / off road diesel cause dirty oil? #3  
It's going to be black, it's just a diesel thing. It will look nothing like the oil in your gas engine's. The black color is caused by soot that enters the crankcase from cylinder blowby. Completly normal and nothing to get upset about. The "look" of oil means nothing, the only true way to tell is to do UOA's (used oil analysis).
 
   / off road diesel cause dirty oil? #4  
I agree with Deiselpower, There is probably nothing wrong with your engine since I have experienced the same results from an oil change at the recommended intervals.

Since I have owned a deisel fueled truck in the past, I can vouch that the oil is much darker when changed than a gasoline engine.
 
   / off road diesel cause dirty oil? #5  
To answer your question, yes, off-road fuel, if it is high sulfur (and it can be...check with your source) will contaminate your oil faster than low sulfur or ultra low sulfur fuel. But it is not something you can detect with your eye.
 
   / off road diesel cause dirty oil? #6  
twodogs said:
I just changed my oil again on my b7800 as I was approaching 200 hours. I change it every 50 hours. I use off road diesel. The oil seemed quite black to me. Is it from using off road, or is it from comparing it to the oil I am used to changing in cars? Am I doing any damage by running the off road diesel?

Off road dyed diesel doesn't make make black oil anymore then on road undyed diesel, its the nature of diesel engines. You don't have to change your oil every 50 hours, every 100 hours is more then adequate and what the manual states. Heck, alot of us would be changing oil every two weeks if that was the case. :rolleyes:


The EPA regulations require that the sulfur content of all diesel dispensers in the United States, except California, be communicated to the diesel end-users, using new dispenser labels. This includes the S15 (ULSD), S500 (LSD), and S5000 (HSD) dispensers. The EPA has defined the text for each label and provides specifications as to where the label is to be located on the dispenser. This regulation applies to any dispenser; whether it is at a retail site, commercial site, or is for company's own use.


I don't know if any state is using HSD anymore. We only have ULSD here.
 
   / off road diesel cause dirty oil? #7  
cp1969 said:
To answer your question, yes, off-road fuel, if it is high sulfur (and it can be...check with your source) will contaminate your oil faster than low sulfur or ultra low sulfur fuel. But it is not something you can detect with your eye.


Took the words right out of my mouth! :D
 
   / off road diesel cause dirty oil?
  • Thread Starter
#8  
Thanks for the comments gentlemen! I knew that the off road was cheaper due to the lack of road tax. I just wanted to make sure that I wasn't doing any harm to my tractor due to the higher sulfur. I am a newbie to the diesel world.
 
   / off road diesel cause dirty oil? #9  
DieselPower said:
It's going to be black, it's just a diesel thing. It will look nothing like the oil in your gas engine's. The black color is caused by soot that enters the crankcase from cylinder blowby. Completly normal and nothing to get upset about. The "look" of oil means nothing, the only true way to tell is to do UOA's (used oil analysis).

I agree with this guy :D
 
   / off road diesel cause dirty oil? #10  
I agree, it is a diesel thing. BUT, this is primarily because of the imprecise nature of the mechanical fuel pump and injectors used in tractors as opposed to the electronic injectors used in all current on road trucks. In general, the electronic injectors are so much better at precisely controlling the flow of fuel that I can put 10,000 miles on my PowerStroke diesel and the oil is still a long way from being black. In fact, it will only be a little darker than when it was put in. But my Kubota will be totally black within a few hours of changing the oil, as will any mechanical injector diesel that I have ever seen.
 
 
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