'07 A3 2.0t Oil Consumption

[Cody Forbes]

But higher viscosity oil provides more protection to the bearings in  
the bottom end as well as piston skirts. It doesn't get forced out  
from between the bearing and journal as easily when put under high  
stress. In reality you need a compromise of both for cold startup and  
protection when warm. During the summer you should be running thicker  
oil for sure.

We run 20w50 in all of our Porsche race cars. I run 15w50 Syntec in my  
'fast' 5000tq except in the coldest months. Purely for anecdote  
because of the very specialised nature, Top Fuel and Funny Cars run  
straight 80 weight oil because that's what it takes to keep the rod  
bearings from contacting the crankshaft journals when EACH rod bearing  
is trying to support 700+hp.

My point is that lower viscosity is not better lubrication. All it  
means is that oil can get into smaller nooks and crannies and lower  
the oil pressure a bit on cold starts. Thicker oil provides more  
protection, but doesn't get in some of the tight tolerance areas that  
newer engines have as well as bringing the oil pressure dangerously  
high on cold mornings (ask all the PCA racers that have exploded an  
oil cooler at the last/first event of the year). Rub your hands  
together with some peanut oil then with some Karo and figure out which  
one lubricates better.

YMMV, Im not an oil manufacturer, nor am I am chemist, I'm not telling  
you what to do, etc etc, disclaimer, lawyer, blah blah blah. The above  
is just voicing some information I have gathered over a lifetime of  
experiance dealing with high performance engines.

-Cody (mobile)

On Mar 25, 2010, at 11:04 AM, Jeffrey Brown  
<jeffrey.r.brown at gmail.com> wrote:

> Interesting comments on the oil weight.  Where I come from, or at
> least my knowledge of certain cars, is that you always put in the
> lowest viscosity oil you can get your hands on, and this is typically
> Mobil 1 0w-30.
>
> What you describe almost sounds to me like you are making up for bad
> seals or bad tolerances by increasing the oil viscosity at the risk
> of increasing cold weather and start-up engine wear, and especially in
> a turbo car.
>
> My knowledge is specifically about Volvos and older ones (80's-90's
> 200s, 700s, 900s, etc) both gas and diesel.  There is a guy I know of
> who
> specializes in the volvo D24 and D24t engines (which is VW sourced 6
> cylinder) that uses mobil 1 0w-30 in these engines (not the "diesel"
> grade oil)
> and changes at 25,000 mile intervals (not counting filter changed I
> think every 10k).  He's got empirical data to back up this behavior,
> but I admit this is
> an extreme example.
>
> I guess what I am curious about is whether the conventional wisdom in
> audi land is not consistent with this wisdom, and that it is common
> for people
> to use heavier weight oils in general, or for specific applications,  
> etc?
>
> In my case, I was kind of surprised when I found out 0w-30 is not a
> "supported" oil for my A3
>
> --jeff
>
>> Actually, that's not entirely true...both the urq and the S6 lost a  
>> quart of oil
>> fast after the idiots at the dealer put 0W40 new spec oil into  
>> them, even though I
>> had provided the 5W50 and filters.  Used the filters, but not the  
>> oil.  Brainless
>> incompetents.  First oil change with the right oil, they both lost  
>> a little, but
>> since then, nothing  after 3000-4500 miles each oil change.
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