10W-60 is specified by factory for 3.2 V6 in your Alfa, especially when used for sporty driving and high temperature climate.
And this is what this article also explains - if you would be using lets say 10W-40 and push it hard (while air temperatures are also high), this oil would heat up so much that it would behave as if it is xxW-30 oil and start loosing its properties faster, and might not offer proper lubrication at that point. While 10W-60 on the other hand, would heat up more than 10W-40 under the same circumstances, but would still offer proper lubrication.
If I check my handbook for Alfa 166 which has the same 3.2 engine as GT and GTAs, it says to use 10W-40 oil for normal use (for 2.5, 3.0 and 3.2 CF3 engines), and 10W-60 for sporty driving (as these engines have cats in the exaust manifolds, they can heat up a lot!). I still maintain though, that 10W-50 oil is right in the middle of those two and should be used in Alfa V6 engines... as I believe that 10W-60 Alfa recommended because this was the grade Selenia could offer as their high performance oil, and those two have been partners for decades.
The article otherwise tries to explain why someone should be cautious when trying to use 10W-60 in an engine, that does not have this oil grade recommended by the handbook.
Last edited by lizard; 04-10-16 at 15:59.