Audi Junkie

<center><img src="http://pictureposter.audiworld.com/27563/visc2.jpg"></center><p>
Overall lower operating temps mean higher viscosity. Oil visc is related to it's temp. An oil that is 15cSt at +100c (operating temp) will be like 90cSt at +40c (above room temp) Simply reducing oil temp from 220f to 190f will result in the oil being a bit thicker, that's what happens in cold weather. 0w oil will lube the turbo better at start-up. If you see below 0 degrees F get a 0w-XX oil.

My stupid made-up rule on W-ratings-

&gt;+20f=20w
&gt;+15f=15w
&gt;+10f=10w
&gt;+5f=5w
&lt;0f=0w


PS German Syntec 0w-30 is worth checking for if you can hit an AutoZone or two and dig. Pours at -83f!

Audi Junkie

...especially in a V6.

Audi Junkie

As much as I like the German Syntec, I am keeping off of ester oils untill I finish my Auto-Rx treatments. The new Mobil Drive Clean 5w-30 is a Gruppe III synthetic for $1.17 a quart, but is a lil bit thin when hot so I mixed in a quart of Mobil 1 15w-50 and get a 40 weight oil for summer. Now I need better cold-cranking and a bit thinner overall, so now I am mixing it with Shell Rotella Synthetic 5w-40 in the ratio this viscosity calculator tells me to. The new Mobil Drive Clean is a great blending oil as it has low additives and a strong base oil to meet the new GF-4 spec. Mixed with heavy and over-additized oils like Mobil 1 15w-50 (PAO) and Rotella it is the hook-up for $2/q.


You had to ask.<ul><li><a href="http://www.shellglobalsolutions.com/base_oils/toolbox/toolbox.htm">http://www.shellglobalsolutions.com/base_oils/toolbox/toolbox.htm</a</li></ul>

FoKai

awesome reference tool! thanks!

Audi Junkie

For those guys who can't find 0w-40 or 5w-40. Mobil says it's ok to mix grades of Mobil 1. The additives are almost identical across the line. I think that's why their 30 weight oils are so thin, you're SUPPOSED to blend it thicker as needed.

nexus617a4

I am picking it up at a local store. The dealership charges an extra $30-40 for Mobil1, but if I bring in my own oil, they give me $15 off the oil change price to apply to another service (e.g. tire rotation).

nexus617a4

Mobil 1 0w40 it is.