I have several quarts of HD30 oil on my garage shelf. This is described as "all purpose, heavy duty motor oil." Can I use it in my '83 MB300SD?

(Yelled like Bluto in Animal House, right before the food fight...)

OIL THREAD !!

You can use it but you probably shouldn't use it. Get some Delo 400 or Mobil 1 for the crank case and pour a cup of 30 wieght into the fuel tank with each tankful if you really want to get rid of it. Plus you're in Vermont. You'll never get your car started in the winter with 30 weight oil. Splurge on some Mobil 1 15W-50 (~$40) this year and see how much easier cold starts can be.

Sixto
95 S420
91 300SE
87 300SDL
83 300SD

Don't forget Rotella

.... and Delvac 1300, Delvac 1, Ursa...... etc.

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1985 300D Turbo ~225k
2000 F350 (Powerstroke) 4X4, SWB, CC, SRW, 6spd ~148k
1999 International 4900, DT466e (250hp/660 ft/lbs), Allison MD3060 ~73k

IMHO the best oil for any car is Mobil-I period, no second guess,nothing comes close.

However, out here in India, Mobil-I is $40 for a gallon so I am using Gulf single weight turbo rated diesel oil of SAE 40 weight. As I can recall, MB engineers did a comprehensive test with single and multi-grade oil and their conclusion was that single weight oils are far superior to multi-grade, of course no Mobil-I multi-grade was used in this test.

The Guld XDMO SAE40 is one of the few single weight oils which has a turbo rating. In my case, driving at ambient temps of around 50c this oil has proved to be the best in terms of thinning and longeviety.

For ANY engine, single weight oil is not good. I have been to the Middle East and the cars there call for 15W-40, due to the temps(Summer 125 degs.) So with that in mind, there wouldn't be a place in the US where single weight would be called for. As for what to use, I won't get into this debate, just don't use single weight oil for a car engine.

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1999 MB SL500 (110,000 mi)
2004 Volvo V70 2.5T (220,000 mi)
2014 Tesla Model S 85 (136,000 mi)
MBCA member

What if you put 3000 + miles on your car in a two month period when you know that the ambient temps will be 80*F +... Could you use single weight then?

Yes, this is an oil thread!!

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1996 (W210) E300D 86K - Traded in for a Lexus
1992 (W124) 300D 2.5 Turbo 202K - Sold
1983 (W123) 300D, 146K - Sold
1970 280S, 263K - Sold - Beginning of addiction

Guess the MB engineers were totaly wrong at their conclusion about the advantages of single weight oils over multi-grade. Note, I didnt say that all multi-grades are bad, Mobil-I rules but not all of us can afford that.

Used to use Castrol RX-Plus multi-grade diesel oil and was surprised to see a high consumption, also during summers at 50c outside temps, the oil would be as thin as water.

30W is best used in lawnmowers, power generators, and other such air-cooled small engines. These engines run hotter than automotive engines, and have a tendency to vaporize regular motor oil.

If you don't have any small engines, you could use it as a top-off oil between oil changes.

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95 E320 Cabriolet, 159K

I would do a 100 mile oil change with it along with a little sea foam engine cleaner.

The manufacturers of most small engines today call for multi-viscosity oils today. The only place I use straight grade oil is for chain oil on chain saws.

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Mike

2000 SL500 22,000 miles
1981 300CD 188,000 miles
1979 450 SEL 266,000 miles
2005 Cadillac CTS 25,000 miles

My OM616 lasted for 565000 miles before needing a top end job and this using good old straight weight dino oil and my turbo OM616 runs real quiet with the same oil. I put my faith on MB engineers and I guess havent gone wrong yet.

If the oil is diesel rated (CF, CG, CH, CI, etc) then yes, it's safe to use in your diesel. If it is NOT diesel rated, and only has spark-igntion (gas) ratings like SH, SJ, SL, etc... then do NOT use it. Many oils don't have the Cx ratings and these should NEVER be used in a diesel engine, especially an indirect-injection diesel like MB's due to the soot generated. The Cx oils are designed to suspens soot safely, Sx oils are not. 30w is fine, btw, as long as ambient temps are above approximately 40F (otherwise you'll have trouble starting the car).

For the record, I agree with Sixto. Add a pint per tank of gas to use it up, and run Mobil-1 15W-50 instead. It's worth the cost, IMO. I use Mobil synthetics in all my cars and love the stuff. I run extended drain intervals (7.5k-15k) with oil analysis to offset the slightly higher cost.

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Dave
Boise, ID
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