I see that the V8 specs 10W-60 or something like that? Why is it that the viscosity requirements are so much higher than that specified for the V12 (0W-30 or 0W-40 Mobil 1)? What is different about this engine that it requires a 60 weight?

Geez, it's not a Harley

 

5W-50 is also supposedly acceptable but I totally see your point.

 

It was reverse engineered from an old Russian Diplomatic Zastava

 

The E46 M3 also requires 10w-60, supposedly because the high piston speed necessitates an oil viscous enough to stick to the moving parts. In the case of the Vantage, I don't think the piston speed is as high, so it's probably a precautionary measure. I'm actually going to try 5W-50 with my next oil change.

 

On the same note, how many miles are you guys changing your oil?

 

This same issue came up as a result of PitbullSL500's trip to the dealer (which subsequently lead to him selling the car).

https://www.6speedonline.com/forums/...-3-months.html

Apparently AM changed it to 5W-30.

 

I just picked up some Castrol 10w60 online for $9.75/qt

 

How much do I need? 12 liters or 12 quarts?

 

my file states 11 quarts or 10.4 liters for engine sump (encl.filter)