Diesel Oil Change: how long before oil looks dirty?
Just had the Service Schedule A done on my 2008 ML 320Cdi on Thursday. I probably have driven about 30 miles max since service. I checked the oil today out of curiosity to see if it was clean; it is black. Is this normal for a diesel? How long does it normally take for the oil to look black? Its my first diesel. Thanks!
Instantly. In 1980 I purchased a new 300CD and kept it for 14 years. I did all the maintenance. The oil was black the whole time I owned it. I changed the oil on average every 5k miles. I work for a large wireless (currently #1) company and I have over 500 diesel generators that are used for power backup. Same scenario, change oil and check it and it's black. Don't worry about it. Just change it and your vehicle will giver you years of service. One note about diesels that was shared with me by an MB engineer regarding my 300CD. He told me to put one quart of ATF in the tank once a month and also fill the new fuel filter with the ATF when changing it. He advised that this kept the injectors clean. During the 14 years I owned the car, I never had an injector problem and the engine ran flawlessly. Did the ATF do it? I don't know but when I traded it in, the mechanic who checked it out for the dealer ended up buying it because the engine ran so well.
Instantly. In 1980 I purchased a new 300CD and kept it for 14 years. I did all the maintenance. The oil was black the whole time I owned it. I changed the oil on average every 5k miles. I work for a large wireless (currently #1) company and I have over 500 diesel generators that are used for power backup. Same scenario, change oil and check it and it's black. Don't worry about it. Just change it and your vehicle will giver you years of service. One note about diesels that was shared with me by an MB engineer regarding my 300CD. He told me to put one quart of ATF in the tank once a month and also fill the new fuel filter with the ATF when changing it. He advised that this kept the injectors clean. During the 14 years I owned the car, I never had an injector problem and the engine ran flawlessly. Did the ATF do it? I don't know but when I traded it in, the mechanic who checked it out for the dealer ended up buying it because the engine ran so well.
Not exactly right. The #1 wireless company is in China.
True that the engine oil looks black just about immediately once you turn engine on the first time. This does not mean that the oil would not be good.
The ATF idea probably isn't good with new diesels with particulate filters etc. but I leave that for engine experts.
ATF is not recommended as an additive by Mercedes. It tends to coke the injectors. Filling your fuel filter with it every couple of years when you change them is not an issue. Pour clean fresh oil in your crankcase from about one foot up and you will see that it turns black about six inches before it gets to the filler hole.
It's not on a brand new engine, but once the oil does get black (2-3K miles) it will indeed be black forever after, including instantly after the next oil change.
In any event, oil color has NOTHING to do with quality of oil or remaining life left in oil on any kind of engine.
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Kent Christensen
Albuquerque
'07 GL320CDI, '06 E320CDI
Main issue is, that you can't drain much more than 90% of the oil from those engines. The sod in the old oils is so strong, that will stain new oil right after first start up. I do have older Perkins engine in my welder, that keeps the oil clear for hours after change, but no oil cooler and straight 3-cylinders.
Main issue is, that you can't drain much more than 90% of the oil from those engines. The sod in the old oils is so strong, that will stain new oil right after first start up. I do have older Perkins engine in my welder, that keeps the oil clear for hours after change, but no oil cooler and straight 3-cylinders.
I don't want to have the last word on this issue but one clarification: new MB engines are designed for siphoning, the oil dipstick tube goes to the lowest part of the pan, if you do it properly, you don't get any oil from the plug.
You did not seem to claim that the sludge does not come out this way, this is a common argument. However if one does have that with modern oils and modern engines, then there are some real issues, other than just getting that out of the engine. (no more comments on this topic from me for this thread).
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