I just picked up a case (6 quarts) of 0w-40 for $21 including tax. Thats a screaming deal to me. I have been meaning to try this stuff for a while for summer. I have been using M1 10w-30. Im sure there are people out that that think im nuts for using this stuff. I just want to know if anybody else has used it. If not, ill be a willing test subject. I do 5k mile oil changes. The 0w part does not really concern me because it never gets below 60 degrees in SoCal anyway. I was looking for 5w40 truck and SUV but nobody seems to carry it around here. Just want a good 40w oil for the 110 degree trips to Vegas.
Thanks
Justin
94 960 99k

Sure, this is what I use in my son's 960, year around. It's the best oil out there, save for some of the more esoteric and more expensive synthetics. It's Mercedes' oil of choice these days.

Folks should give themselves an education by visiting the Mobil 1 Web site for Sweden. Or Germany. Or the UK. There, you'll learn that 10W-30, 5W-30, etc. formulations are not even available.

The bottom line on these oils is that they are nothing more than an attempt to maintain corporate average fuel economy numbers (at customers' expense IMHO) by USA manufacturers, and apparently Volvo feels its USA customers will be unduly influenced by this BS and consequently specifies these oils in its USA owner's manuals. It doesn't reflect the reality of how Volvos are run in Sweden or the rest of Europe.

http://theoildrop.server101.com/ubb/ultimatebb.php

Mobil-1's 0W-40 has about 40% higher viscosity at 100C than their 10W-30. Oddly, despite the "0W..." low temp rating, its 40C viscosity is also significantly higher than the 10W-30. I'd call it a warm-to-hot climate oil, for higher mileage engines, with better initial startup lube capabilities than the 15W-50. But I would not recommend using it in cold weather.

When you note that Volvo recommend ordinary 10W-30 for everything except extreme duty (like trailer towing in hot weather), and for those extreme duty conditions, they recommend 15W-40 or synthetic, it sounds like there would be very little high-temp advantage to synthetic 0W-40 over 10W-30. And the 10W-30 covers you better in 'cold' starts, which is where the engine sees its worst conditions of marginal lubrication.
--
Bob (son's 81-244GL B21F, dtr's 83-244DL B23F, "my" 94-944 B230FD; plus wifemobile Dodge minivan, hobbycar MGB, and numerous old motorcycles)

I am also confused. I was under the impression that you want a think oil at low temps like start up and a thick oil when it gets hot. So low first number high second number.
Thanks again for everybody's input. I feel better about using this oil especially if MB and Porsche are using it. Thanks again.
Justin

I'm confused on what you're saying has better "initial startup lube capabilities"... You say that the 0W-40 would be better than the 15-50 for startup, but the 10-30 is better than the 0-40? I might be missing something, or understanding it wrong, but if the 10-20 is better at startup than the 0-40, wouldn't the 15-50 be better as well? Doesn't the 0-40 have better startups than all of them?
--
Kyle - attending Ore. State, while my lil '68 142 (256k, 74 b20, m40, iPd bars, other misc... =D) waits for its next outing... (My Cardomain site)

First number is the "winter" (hence, 10W) viscosity rating, the second is the summer, or high temp rating. The higher the number the thicker the oil (higher viscosity, or resistance to flow). Ideally we might like a 0W-40 or 0W-50, to give best of all worlds. Mobil claim this with their "Euro-formula" 0W-40, and their specs say it has significantly higher viscosity than their 10W-30 at 100C, but also show it has higher viscosity than their 10W-30 at 40C, so this is a little puzzling. Perhaps the viscosity at 0C (the temp at which oils get their "W" rating) does dip below the 10W-30?

My oil philosophy - use the best quality which suits the application and passes my cost/benefit "sniff test". That's Mobil-1 in my view. And use the thinnest oil which will still meet the highest temperature conditions I expect the engine to see. That's 0W-40 for our cars in California and, for my son's 81GL when he's at college in western Canada, 5W-30.
--
Bob (son's 81-244GL B21F, dtr's 83-244DL B23F, "my" 94-944 B230FD; plus wifemobile Dodge minivan, hobbycar MGB, and numerous old motorcycles)

I also use 0W-40 in my V90, based on the recommendation of my master Volvo mechanic friend who also uses it in his 98 S90. His working side by side with the MB techs may have had some influence...nothing but 0W-40 goes into those cars, and I think more cars in general.
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John Shatzer, '97 V90 @ 105K

I use M1 0W-40 in both our 95 960 152,900 and our 98 S90 69,590 for the last 6 months. It's the soonest I was able to obtain any. I am using 7,500 mile OCI's. Previously I was using M1 10W-30 which served me very well. The M1 10W-30 is a 'light' 30 weight, actually closer to a high '20' weight. The 0W-40 is closer to a midrange '40' weight by API specs. Should be great for your use.

DEWFPO
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1998 S90 068,300 and 1995 964 152,300

Thank you for both your responses. The fact that somebody is using 15w-50 puts my heard at ease. And I thought I was some kind of trail blaser. HA!
I had no idea about M1 10W30 being a light 30 weight. After looking at the Mobil 1 web site, i see what you mean (cSt @ 100º C 10.0 ). My car sounds like a sowing machine most of the time, even when the engine is hot. Nothing wrong with it. Most 960s and 850s I see sound the same. I think its the valve lifters. The synthetic 10W30 cured a rough start issue i had after the car had been sitting for more than 2 days. But the 30 weight seems too thin for the kind of weather were about to have down here. I hope 0W40 is an oil i can use all year round.
Should I expect a fuel economy drop from the thicker oil? I get 23-25 in mixed driving.

I noticed no change in fuel mileage going over to the M1 0W-40 from M1 10W-30. The engines still sound like sewing machines as you describe, maybe just ever so 'slightly' quieter when hot.

DEWFPO
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1998 S90 068,300 and 1995 964 152,300

Never tried 0w-40, but I have been using Mobil 15w 50performance formula for a year. I do regular 4500+ rpm levels so I feel better using this type oil. This is always a very speculative subject, all depends on how you drive. If you rarely push high rpms for extended periods, the benifits could be marginal.

www.mobil.com/USA-English/Lubes/PDS/GLXXENPVLMOMobil1_15W-50.asp

Been using M1 15w-50 in my 245, but regularly hit 5k rpm's. I've never used it in the 960, only 10w-30. I would think that for the desert Southwest in July on a long highway trip the 15w-50 would be best over the 0w-40, which would be a better choice for normal driving in the other cooler months.
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'89 245 Sportwagon, '96 960 sedan