You guys worry to much I buy 15w-50 or 5w-40 whatever Walmart has when I am their.

I had zero problems or issues with 15w-50 last winter. Remember it is synthetic and doesn't get as thick as dino in the winter.

This summer I noticed with the 5w-40 on real hot days I will lose maybe 1/4-1/2 of a bar of oil pressure at idle. So what if it idles at 1 bar insted of 1.5, it is still well within MB's specs.

Oil consumption with both is zero and leaks seem to be unaffected.

Just buy whatever is their if your engine is in good shape it will be fine.

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1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

MB says it is fine to use Mobil 1 15W50 in gas and diesel engines in their Factory Approved Service Products sheet from November 2001.
-Joe

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'81 MB 300SD, '82 MB 300D Turbo (sold/RIP), '04 Lincoln Town Car Ultimate

Sooner or later every car falls apart, ours does it later!
-German Narrator in a MB Promotion Film about the then brand new W123.

Okay, that's what I thought. What is different about their truck & SUV blend that makes it better than other Mobil 1 blends?

Thinking about viscosity at different temps, does anyone know of a source to get viscosity curves for different oils? I can get viscosity at 40 and 100*c off the Mobil 1 site, but I'd be interested in a graph of the viscosity of synthetics and straight-weight oils from, say, 0*F to 300*F or something... Does anyone know of a good source for such information besides spending hours in the university library and emailing companies?

Try
http://www.bobistheoilguy.com/

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'81 MB 300SD, '82 MB 300D Turbo (sold/RIP), '04 Lincoln Town Car Ultimate

Sooner or later every car falls apart, ours does it later!
-German Narrator in a MB Promotion Film about the then brand new W123.

I have found M1 Truck & SUV or Delvac 1 to be just fine for year round use in my 72 220D. Thousands of miles and she runs much better now with M1 than she ever did with Rotella. Less smoke, less noise, less starting problems. There is no oil usage in 4k miles between changes, or leak down/blow by that I have seen

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clay

2002 s430 - Victor, a Stately & well tailored chap
1974 450sl - Frosch - Two tone green
1986 SDL - Polei

retired models-
1976 300D - Blei Vanst - it looks silvery
1972 220D - Gump - She was green, simple and ran
1995 E300D - Gave her life to save me against a Dame in a SUV
POS 1987 SDL - Beware Nigerian Scammers

I have been contemplating that, since the manual only calls for a max of 30 weight oil. What is your oil pressure like at a hot idle in summer, and how fast does it come up on a cold start in winter?

I'm still trying to find viscosity figures on Mobil 1 down at 20, 0, and -20*c to see how the cranking viscosity would comapre to the weights of oil that the manual calls for at cold temps. Mobils online tech help has referred me to their technical support 800-number, which is closed right now.
Bob is the oil guy doesn't have anything quite like what I want up on his site, so I'm waiting for replies on that board for any more info.

From personal experience I know on those 0 degree winter mornings my SDL would crank over much much faster then my dads truck when I started them. Both vehicals had new batterys and I6 engines under the hood. His truck with dino 10w30 or 5w30 (don't remeber exactly) would crank very slow then speed up and catch. It hated cold starts.(1994 F150 with fuel injected I6) The 603 on the other hand with supposidly thicker 15w-50 in the crank case would spin right over.

This synthetic stuff is great in the winter!

__________________
1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200