Searching through the archives, I have learned that there is a different type of oil for my diesel.

For the last 40K I've been using "gas" oil. I change every 3-4K,HOT ect. I'll assume I haven't done any real harm,but,should I use a case flush? The old has 165K on her.

I'd like to know soon as I'm off tomorrow and would like to change the oil (with the right stuff).

Y'all are GREAT,

Mr. BILL

90 300SE
85 300D
84 300SD (sold)

As I'm certain Larry Bible (the self-appointed frequent/hot oil change proponent) will tell you, there are indeed oils manufactured specifically for diesels. Personally, I use Shell Rotella. Chevron Delo, and the new Mobil1 Delvac(?) are others with the diesel grade specification. I think they have higher detergent contents or something...

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Matt
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Grey/black '84 300D, 194K

Yes, these oils are termed "Universal Grade". I don't know where that comes from, I suppose because they can be used for diesel and gas engines.

I don't know what oil you used previously, but it should have a "C" classification, such as CF or CH. I doubt that you did damage, and I wouldn't worry about flushing it. The best way to "flush" it would be to pull the drain plug after the engine has reached operating temperature(at least 17 miles of driving) and let it drain overnight.

I have used Chevron Delo 400 Multigrade, but Shell Rotella, Mobil Delvac are all good diesel engine oils. If you really want to give your engine a good diet, put it on the new Mobil Delvac One, which is Mobil One synthetic in universal grade for diesels. I doubt that it is inexpensive, and you will probably have to find a truck stop to get it. If you're interested, you can probably call your local Cummins or International dealer to find it.

Good luck,
Change oil hot, and change oil often,

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Larry Bible
'01 C Class, Six Speed
'84 Euro 240D, manual, 533K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in
Mercedes automobiles

The early and mid eighties diesels called for CD rated oil (now an obsolete rating). I suspect the newer SJ rated gasoline oils are better than the old CD oils in just about every respect. They don't have to neutralize sulphur as much because of current low sulphur fuel. You won't hurt your car by using them in a pinch although it's just as easy to use 15W40 oils.

If you are really convinced about the C* rating, Valvoline VR1 Racing Oil has a SJ/CD/SH API rating. It comes in different grades, 40, 50 and 20W-50 which I use in my '80 300D oil burner. I'm kinda sold on the C* thing also and after trying many other oils, I am most comfortable with this one. Maybe its just the power of suggestion but my engine seems to run smoother. You can get it at Walmart for about $1.69 @ qt.
Would it be a bad idea to use 40 or 50 in summer to decrease oil consumption?

Although there are many oils with a C rating, and probably the ones that don't have it on the can, could probably pass an early C rating test, the universal grades are much better suited for diesels. They contain a greater amount of cleaning agents and additives that can disperse the soot better. After all, these oils have been developed specifically for diesel engines.

Good luck,

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Larry Bible
'01 C Class, Six Speed
'84 Euro 240D, manual, 533K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in
Mercedes automobiles

Check this site out. Click on "Info":
http://kozmik.guelph.on.ca/gtdproject/

Larry.
I may not be the sharpest pencil in the box, but, your last sentence confused me. "After all, these oils have been developed specifically for diesel engines."
Are you speaking of the universal grades which you said meet the early C rating or the C rated oils?
Thanks

When I refer to universal grades, that is the term for the oils developed and marketed specifically for diesel engines. Examples of universal grade oils are: Chevron Delo 400, Shell Rotella T, Mobil Delvac, Mobil Delvac One, etc. If you go to a truckstop, these are the oils you will find. Typically they will be in 15W40 grade.

If an oil has a C rating, it is not necessarily a universal grade, developed for diesel engines oil. BTW, these oils work quite well in gas engines. Their added cleaning agents will keep a gas engine spotlessly cleaned internally.

Good luck,

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Larry Bible
'01 C Class, Six Speed
'84 Euro 240D, manual, 533K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in
Mercedes automobiles

If you just stick with 15W40 oils you should be OK. I have never found one-house brand, generic, or major brand-that wasn't fully rated for diesel engines. Most are also SJ gasoline engine rated, although Texaco has a heavy duty rated diesel oil that is diesel only, no SJ rating.

I found oil at Advanced Auto Parts here in Austin that sells their own brand of "Premium Diesel"with a C rating for $1.04 a qt.

I am going to give it a try.

Mr. BILL

90 300SE
85 300D
84 300SD (sold)

The Universal grade oils are the ones that are formulated specifically for diesel engines. These are oils such as; Chevron Delo 400, Shell Rotella T, Mobil Delvac, Mobil Delvac One, etc. You will find these oils at the truck stop or over the road truck dealers. For that matter, I buy Chevron Delo 400 multigrade at Wal-Mart now. These are typically used in all climates in 15W40 grade.

Just because an oil has a C classification, doesn't mean it is universal grade. The universal grades have added detergents and additives for soot dispersal. These oils work quite well in gas engines as well. They will keep a gas engine quite clean inside.

Good luck,

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Larry Bible
'01 C Class, Six Speed
'84 Euro 240D, manual, 533K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in
Mercedes automobiles

Mr. Bill, I have used the Advanced Auto Parts 15W40 as well as other generic and house brand 15w40 oils with good results. They are probably bottled by one of the major companies, just without all the advertising costs added on. Right now I am using Coastal 15W40 Fleetoil from Autozone for $3.99 a gallon. I have also used Pep Boys 15W40 housebrand. Just whatever is handy.