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Cause of diesel engine oil turning black almost instantly?

72K views 10 replies 10 participants last post by  sachin  
#1 ·
What causes the oil to turn black almost instantly on a diesel? You can put new oil in it and with in a couple of minutes it turns black, what does it?
 
#2 ·
Hey beaslyb

The oil goes black within a couple of minutes of running because their is 2 to 3 liters of used(old) oil in the high pressure oil system, and a smaller amount in the low pressure system that does not get changed when doing a oil change. when you run it the new and remaining old oil mix, giving you the appearance that the oil has already dirty. The original source of the "black or dirty" looking oil, is from the blow-by of soot from the exhaust past the piston rings. Their are more reasons but I would say those are the main reasons.
 
#3 ·
What cmilanij said is correct. You can help this by changing oil more ofeten and running additives. Make sure your engine is running good. I run the lucas oil additive for powerstrokes and change my oil every 4000. It looks really good, about the same as a well maintained gasoline engine.
 
#7 ·
To each, his own. I find it a bit wasteful to change that frequently. I've pulled an OA at every change to track fuel dilution, using Blackstone Labs. Every one has come back with extremely good wear #'s, sheared to 30wt, but still usable at 7.5k. The truck runs great, and has no issues at all. They tell me my 6.0 is doing fine & looks good.

OMC
 
#8 ·
The oil is turning black because it is cleaning the soot out of the engine. Oil has 3 functions in any engine, Cool, Clean and Lubricate. Stay away from the oil additives if you run a good oil ( rotella- mobil -delo) there is no reason for any additive. If you are spending money on additives you're a fool. A good diesel engine oil has all of the additives already in it. If you go adding junk to it. It can cause the additives that are in the oil to drop out. A conventional base oil can only hold about 25% additive untill they start droping out.
 
#9 ·
I ran a short (2500 mile) oil cycle at 25,000 miles and it cleaned my oil up nicely. The oil was still translucent at the end of the following 5000 mile run. I plan to do it again every 25k. Some oils also have more detergent additives than others (calcium, magnesium, phosphorus) and do a better job of dispersing the soot so it can be filtered more efficiently.
 
#11 ·
cause of Diesel Engine oil turning black instantly

What will be the cause of Diesel Engine oil turning black instantly in the green engine.
Here my query is for newly manufactured BSIV diesel engine oil turns black instantly just after first fire of engine on test bed only.
Which component of engine will contribute to turns engine oil block?
I guess following components will contribute but then what will be the percentage of contribution.
EGR- Exhaust gases Recirculated
Turbocharger
And piston oil rings