To say that an oil has a CCS of 3800 or 7000 means nothing. You need a reference temperature. For example, Mobil 1 15W-50 CCS specs are 7000 centapoise @ -20C. This viscosity at -20C. is very good for a 15W-50.

Shell's Rotella T has a CCS of 6400cp@-30C. It is much less viscous than Mobil 1 15W-50, thus the 5W vs. 15W.

Back to my statement that you questioned, Mobil 1 15W-50 has the same CCS rating as dino Rotella T. Yes it does. They are both rated 7000cp@-20C. Neither oils are good candidates for very cold weather operation, IMO.

Delvac 1300 15W-40 appears to have the best cold cranking properties of the dino 15W-40's at 6000cp@-20C. It meets the 10W cold flow requirements, despite being marketed as a 15W.

You ask where I get my info. Prior to finding this listing http://www.bestsyntheticoil.com/amsoil/technical-data-bulletins/Specs-June-17-2003.pdf , I gathered info from Product Data Sheets, MSDS, and/or by emailing the different companies. I have found a few typo errors in the link above but for the most part it is accurate and up to date.

Okie -

Great link - very informative. I do notice that there's is a big swing in the some of the numbers - for example the Mobil 1 15w-50 CCS went from 5200 when tested in Feb 30 to 7000 when tested in March 03. Some of these numbers are considerably different from the numbers posted on the products website - Delvac 1300 looks close, the Shell products don't, and of course the Mobil 1. Obviously the manufacturers have a dog in this fight, so their objectivity can be questioned. Is this link sponsored by Amsoil or are they just hosting the results? Either way, interesting stuff. My personal experience w/ the Mobil 1 15w-50 has been easier cold weather starts, but then it rarely gets colder than 15 degrees or so here.

__________________
Tjohn

82 300 SD
77 450 SL (gone)

Mickey Mouse,

Deckerville? even further up than I thought. Don't think I've been there, but I have been to Sandusky.

Marquette. Now that's where it's cold. Once I met this guy in Germfask (NE of Manistique) who spends his winters in the Upper Peninsula and summers in Alaska. He and his wife beed sled dogs. I think he said his wife was Susan Butler (who has won the Iditerod dog sled race several times). It just struck me funny that it was 20 deg below zero at the time and this is where he goes for winter warmth.

__________________
Michael LaFleur

'05 E320 CDI - 86,000 miles
'86 300SDL - 360,000 miles
'85 300SD - 150,000 miles (sold)
'89 190D - 120,000 miles (sold)
'85 300SD - 317,000 miles (sold)
'98 ML320 - 270,000 miles (sold)
'75 300D - 170,000 miles (sold)
'83 Harley Davidson FLTC (Broken again) :-(
'61 Plymouth Valiant - 60k mikes
2004 Papillon (Oliver)
2005 Tzitzu (Griffon)
2009 Welsh Corgi (Buba)

Yes, the difference in Mobil's Trisyn and the more recent Supersyn formulations is quite significant. I'm not suprised by the difference in specs.

The list is put together by Michael Kaufman. It does appear that he is an Amsoil dealer. The only problem I have with the list is when a manufacturer refuses to publish a certain spec, the minimum allowed is entered. For example, the list gives Delvac 1 a HT/HS value of 2.9 which is lower than actual, but is the minimum allowed for that viscosity. Most of the Data is available from the manufacturers but some is not. I disagree with Mr. Kaufman, I would leave the unknowns blank.

Both of the entries to which I referred were for SuperSyn. However, I suspect your next point reflects the reason for the difference in specs. . .

On the CCS viscosities, there is no official value posted for M1 15w-50 I could find on Mobil's website. I suspect that in this link the minimum (7000) was entered for this value. It's still a very good link, and one I'll keep as a resource.

__________________
Tjohn

82 300 SD
77 450 SL (gone)