What color is your guys oil when you change it? All the other diesels ive messed with it is always black a few minutes after running. The oil in my truck looked like a gas motors oil when i changed it today (just dark brown, little over 3500 miles). (I bought the truck used, thats why im curious). Also, is it an intercooled motor?

Mine is BLACK after @ 5-6 thousand miles when I change it.

Ben

Dirty oil means, the oil is doing it's job correctly, keeping the inside of the engine clean, and trapping dirt, soot and combustion products.

Lot's of good oil information here.http://www.dieselplace.com/forum/images/smilies/rockon.gif (http://www.bobistheoilguy.com)

i was just curious, as i said all other diesels i know turn the oil black in minutes.

Yes, Pick is right on the money. Dark oil isn't a bad thing!

Even though your oil may look clean on the dipstick it will still come out dirty. Also changing at 3500 miles seems a little early for these motors. I just put over 3k on my oil and reading the oil life still shows %. I change pretty regular at k but sometimes extend it to 6000 between changes.

Diesel oil has an additive to keep the soot that gets by the rings suspended. Since not near as much soot gets past the rings in the Duramax it takes longer to turn black. Mine still looks brown at 3K. Later! Frank

without egr blocked, it was black at 5grand. with egr blocked its just a bit darker then when it came out of the bottle at 5 grand.

My oil stays pretty clean too compared to the diesels of an earlier generation. MY 21 year old Mercedes diesel car turns oil black quickly, but the Duramax gets darker on the dipstick similar to a gas engine, at least for the first couple of thousand miles.

I always assumed it was due to the more complete combustion of the modern super high pressure Bosch FI set up, compared to the old fashioned mechanical injection system.

To answer your 2nd question, yes Duramax is intercooled

Our fire trucks show REALLY dense black VERY quickly. At 17,000 miles on my oil with Oilguard bypass, the oil looks black at first, but on a paper towel it fades lighter pretty quickly. The fire trucks stain a paper towel BLACK like an ink stain. SPICER

Yeah i was used to oil being black very quickly, thats why i asked. Thanks for the replies guys. Also, what do you mean by blocking the EGR?

I have 13K on my truck with no oil change. The oil still looks like it did the day I picked it up at the dealer. Do you suppose the propane and bypass filter has anything to do with it? I'm going to do oil analysis at 15K to make sure everything is cool.

Maybe the black oil has to do with how well the oil is drained in the first place?I think the Dmax does drain out completely.I have diesels in forestry equiptment that dont drain good.But they have remote filters and lines ,oil can hide in there.Its hard to get it all out when your talking about several gallons of thick oil?