AudiPutz

The link below to this article that appeared several times on this board seems to suggest that Mobil 1, Amsoil and Spectro are superior lubricants.

http://rconcepts.com/beard/dragnet/drag/oilinfo.html

I've read it thoroughly and was a little surprised why the author picked these three brands as winners. Nothing seems to indicate in this IMO unbiased article that any of the oils listed are superior to others. It is not a comparative test. All of the data are supplied by the oil makers and the author just explains the terms by which oils can be judged.
Check the sentence below from the DragNet link and the one below it which can be found on several other web site (listed below) having the same article by Ed Hackett. The sentence is right below the second table of that article.

"The more expensive synthetics; AMSOIL, Mobil 1, and Spectro offer the only truly significant differences, due to their superior high temperature oxidation resistance, high film strength, very low tendancy to form deposits, stable viscosity base, and low temperature flow characteristics."

"The synthetics offer the only truly significant differences, due to their superior high temperature oxidation resistance, high film strength, very low tendency to form deposits, stable viscosity base, and low temperature flow characteristics."

http://vger.rutgers.edu/~ravi/bike/pages/pages/docs/oil.html

http://www.nvrn.vrn.ru/auto/auto.msk.ru/auto/ehoilfaq.htm

http://lonestar.texas.net/~jrh/oil_faq.html

Which one do you trust?
IMO somebody's trying to sell these three brands. I hope you guys on this board are not using Mobil 1 based on this one sentence and the fact that Porsche got a deal from Mobil.
I'm not trying to say that Mobil 1 is a bad oil but without an independent synthetic oil comparative test, i.e. hard evidence, I think that it doesn't really matter which one you use.
Before that happens I'll stick to Castrol 5W-50 which numbers in the article's table look damn good. ;-)

2000 A4 Avant 1.8T MSS
1990 V8

Kevin K

To see the difference in synthetics you need to look at the mfg spec sheets. I put the Castrol site below.

But looking at your 1st ref may explain the sludge problem I had in the past, and noted here severally. When SG rated, your 5-50 had a high 1.2 ash/krud rating. In ref 2,as an SH, the specs changed, including less zink......a usual contributor to ash. And my current ref (SJ) below shows a lower ash rating (.95) than the 1st ref. So perhaps they fixed the krud problem.

Why Mobil-1? Reputation (longer track record), and the cold end of the user range. Look at the synthetics. Both M1 5-40 and 10-30 have pour points of -65F, vs Castrol 5-50 of -38F, and 10-30 of -27F. Big difference (the pp of regular mobil 5-30 is -33F). [note that the Castrol Syn pour pt data in your ref tables appears to be wrong, based on Castrol's site]

The Castrol 5-50 is too thick for anything but the track. At the usual 40/100C spec visc temps, the 5-50 is 120/20 cSt (mobil reg 20-50 is 150/18). Usually, 10-15 cSt is the target at 100C for best peformance. M1 5-40 is 84/14, suggesting less turbo lag. M1 10-30 is 67/10.3 cSt, and Castrol 10-30 is 70/11 cSt. All numbers synthetic, except the mobil 20-50, as noted.

Castrol 5-50 now looks fine for hot summers, the track, or 300 hp 1.8T's in all but very cold weather. It does have a high HTHS 300F rating of 4.8 . But don't use it as an all climate oil. If it must be Castrol, use their Syn 10-30 in cool weather, and their Syn 5-30 in the extreme cold.

www.castrolusa.com/castrolauto/castrolProducts.nsf/(WebProductsMotorOils)

axel

Kevin, I'm using M1 0w-30 in the winter, wash. state . What do you think ?? Axel

Kevin k

M1 -30 is similar to the 5-30. Which engine, how hot does your oil get? Should be fine for winter.
I would switch to 10-30 for summer. (5-40 and 15-40 summer options)

Bobolo

but it seems everyone uses the 10W30 thru-out the summer. is the 10W30 sufficent for say a 10 hour highway drive at 80mph+? the Mobil1 site said it works fine for internal temps up to 475^ how hot does a 1.8t get under prolonged high speed driving?

Kevin K

How hot does your oil get?

Dave M

...due to the large amount of viscosity improvers that are required to get such a large range in that formulation. Many car manufacturers advised against the use of this viscosity in their engines for these reasons. Now a synthetic oil in that viscosity would probably be OK (most synthetics require very little viscosity improvers), but I would stay away from conventional oil in that formulation (if you can even find it).

Dave M - '97