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appearance of used diesel motor oil

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whenever I've seen diesel motor oil that's being changed out (even at normal service intervals), it has a VERY dark black appearance. Is that just what happens to oil inside a diesel engine, or a sign of trouble?

how does the formulation of diesel motor oil differ from that of gasoline motor oil?

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Better Filter

G.G.;
As Marshall replied; the function of the motor oils detergent properties is to hold the paticulate items in suspention.The filters we use sieve size only traps those solid contaminates larger than the sieve size. The smaller the sieze size the more restrictive and the need for higher oil pressure for the oil to pass through.When changing your engines motor oil always try and have it at operating temperature to more have the motor oil wash the inside of the engine.There are better filters that can remove the contaniments.These filter are used on large stationary diesel engines.The use as a filtering media fullers earth and cotton waste.To filter motor oil completely you would remove all of the additives and you would have base mineral oil. A simple test to determine the amount of contaminat you have in the motor oil is to use a multifold of toilet tissue.From the dipstick drop a small amount of oil on the tissue.As the oil disperses on the tissue you will see the contaminants at the center of the spot and cleaner oil at the outer diameter. Just use recomended oil and change it as you feel is required; afterall oil is less expensive than an engine.
Happy Trails Beep Beep from Spiderman:p :p :p

zak
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Talk about comprehensive answers, great !

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soot suspension properties of synthetic

we all know the cold-weather advantages of running synthetic oil. how do synthetic's soot sequestering/suspending properties compare to those of dino oil?

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oil

I have a ' 87 300D Turbo with 220,000 miles. I'm aware of the advantages of Mobil 1 synthetic oil. My question pertains to the oil change interval. MB manual states that for (non-synthetic) oil change intervals to be less than indicated miles (3,000) for engines under stress and that turbo engines were always considered under stress. So how does that extrapolate to oil change intervals for synthetic oils?? Would extended unterval between oil changes invite problems due to greater quantity of particulate matter in suspension?
thanks,
Jan

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Go by the Odo

G.G.;
You know my w123133 300DT with 281k miles and still going strong.
It has been over 5k miles since last change. I went over my interval miles as I went to New Orleans this week end.
At this distance the oil level isn't low enough for the addition of 1 qt. I IS BLACK as it is suppose to be if the detergent properties are doing thier job.
I use Dino oil and always have, 20-50W Penzoil and filter with 1 qt. of Shalers Rislone. I always try to let the turbo cool before shutting down the engine.
I'm not sure whiether this fits into MB recommendations as with the newer diesels?
When the timing chain was replace this past spring; the area under the cam cover was wipe clean, no build up of oil sludge just a nice clean interior.
M.Booth has explained it as no one else could, oil analysis.
I use the toilet tissue test as we did at G.M.
Oil is cheap; let your conscience be your guide.
Happy Trails Beep Beep from the Spiderman on the Gulf Coast

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Ya know, Dr. Booth really hit on the key point. The class of duty the engine performs. All highway driving for hours at a time is very good for your engine and its oil. The short trips are another matter entirely. Throw in driving style and things can really go downhill. When the book talks about things that will shorten the oil life life hills, towing, short trips, etc, I keep thinking they ought to also say "and any driving by BobK". I may well have plenty of life left in my oil, but I'm gonna change it anyway. Just did and engine change on my son's car. A very stressed 2.0L turbo gas ricer. Engine suffered oil contamination/starvation. Looking at a scored crank is a terrible feeling. We got a heck of a deal on a used engine and it still cost over $1,300 to do the job. Plus our labor! You can buy a lot of oil for that money.

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