I read the earier posts re this oil in diesels-- all I can find here says for gas engines-- do they make this for the d's or are you using the gasser stuff?


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82 240D

I have always used GTX sae 30 in my 2 diesels, works great. I dont know if it is ment for gas only.

You need to get an oil rated for diesel applications. Castrol does offer this item. Don't know the API or SAE rating codes, but you should be able to get that from where you buy your oil...

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Jeff L
1987 300e
1989 300e
1987 BMW 325

Dusty,
Here's the deal....when your car was made the oil called for by Benz was to have a rating of CD. Back then gas engines called for SF (well maybe it was SG). Today we are up to SJ or better. SJ exceeds CD So on the one hand you are ok with GTX on the other hand there is even better than what Benz called for back then. I think it is safe to assume that if CH-4 were available back then, Benz would've wanted you to use it.
( I think I just clouded the issue some more )

-Larry

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03/83 300D 184k
07/73 280 160k

Larry,

When I suddenly discovered one day that the GTX I had just put in my car did not have the current diesel engine rating, I called the dealer and asked if I should drain and replace it. I was told that the ratings system had changed, not the oil, so if I had been using GTX for 20 years, there was no reason to be concerned about it now.

The only diesel rated oil I found locally was synthetic. Changing 7 quarts of synthetic every 3,000 miles plus a filter gets kind of expensive for a retiree. Just how important to the life of the engine do you consider this to be?

Thanks in advance for your advice.


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Ted
1979 240D

Ted,
Check the local stores again, this time look for the section where the keep the gallon jugs, you are bound to find either Shell Rotella (15-40 with all current diesel specs) and Chevron Delo 400 (15-40 w/ all current diesel specs). And I think I even saw Autozone branded 15-40 oil too, although I didn't check for specs. (same goes for Discount Auto Parts chain here in Fl).
On my 300D, requiring 8qts, buying 2 jugs sure makes changing oil a breeze.
And, if you're a treehugger (no offense), you end up with less plastic waste too!

-Larry

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03/83 300D 184k
07/73 280 160k

Ted,

I always use Castrol GTX 10W-40 in my 300SD and used it in my 240D. Castrol does make a special diesel formulation for diesels called RX Super, but it only is in the 15W-40 grade. I found it harder to start my diesel in cold weather with this oil in it and it seemed to run slightly warmer at high speeds. I'd stick with regular GTX 10W-40. It's recommended for all passenger car engines, gas and diesel, turbo and non-turbo. Synthetic is certainly good, but a diesel with alot of miles should be kept on the same maintenance regimen.

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Rgds,
Aaron Greenberg
MB technician
Precision Motorcars, Cincinnati, Ohio
'67 250SE Cabriolet
'77 450SL
'80 300SD
'85 380SE
'89 420SEL
'93 300E 2.8
'74 Jensen Interceptor Mk.III
'81 DeLorean DMC12
'85 BMW 745i Turbo

Thanks for all the help, guys. Maybe the oil companies could simplify things by putting "put this stuff in your diesel, too" on the label. Sure would help me out.
Dusty

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82 240D

Thanks for the responses, guys. I have always tried to be consistent with the oil I used in my cars, but I don't really know that to be important. I will check around the stores again to see what else I might be able to find.

I think Dusty has a great idea.

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Ted
1979 240D

Dusty,

In a way they do put this on the label, but you have to look for it. As one of the previous replies indicated, look for the C rating. S rating is for spark ignited engines, and C rating is for compression ignited engines.

I'm sure that any oil will work and not HURT the engine, however, the C rated oils have additives that deal with soot dispersal. The important issue is the fact that the byproducts of combustion are quite different between a diesel and a gas engine. The Rotella and Delo that a previous reply referred to are called Universal grade oils. These are the two that are the favorites of the truckers. International truck engines come filled with Delo, and that's what is in the International brand oil containers.

Also to get my oil change fanatical reply, oil change interval is probably at least as important as the oil you use. Sounds like you're doing 3,000 mile oil changes, so you're doing the most important part regardless of the oil you choose.

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

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Larry Bible
'84 Euro 240D, 516K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in
Mercedes automobiles

It sounds like a lot of the confusion re oils stems from the API changing designations over the years. As a diciple of the Drive It Till You Die cult, I give thanks, and will pay homage to all who have driven the same car over 500,000 miles with burnt offerings on the bbq, and also with copius quantities of liquid spirits. Thanks, Dusty

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82 240D

Hey guys!

I just read a story on using diesel oil for gas engines in a car mag. The learned professor of slippery stuff said diesel oil has much greater amounts of detergent and other anti-fouling agents to counteract the foul things in diesel fuel. He said you could keep your gas engine very very clean by running desiel oil which, except for the aforesaid cleaners, is the same as gas engine oil. He especially recommended it for cars that see low miles.

However, if the gas engine is carboned up then beware, using desiel oil will likely cause it to spew great chunks of gunk that was happily residing on the interior of the engine.



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Dean Albrecht
94 E500
99 ML320

Dean,

Can you offer a bibliography?

Thanks,
Larry

I went back to the book store and found they had just put out all new July magazines. I think it was the June issue of Road & Track. Anyone out there know?



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Dean Albrecht
94 E500
99 ML320

Eureka...I found the article in Patrick Bedard's column in the November 1999 issue of Car and Driver. The article was titled, Searching for the right motor oil for "keeper cars", and he had interviewed Ed Kollin, director of R&D for Lubrication Science and ex research chemist for Exxon.

Kollin's advice was as follows:
...for an off-the-shelf blend, he would choose a "heavy duty" oil intended for diesel trucks. Instead of SJ on the can, look for combinations that begin with C (for compression ignition). CG-4 is the latest. A few blends meet both C and S requirements. While the oil part of these deisel oils has the same lubricating qualities as passenger-car oils...the diesels get bigger doses of the additives; up to 80% more ZDDP (the primary anti-wear and anti-oxidant additive), and 30 to 50% more detergent, dispersant, and corrosion inhibitors.


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Dean Albrecht
94 E500
99 ML320