Originally Posted By: PeterPolyol
What's obsolete about it?
Virtually nothing specifies it (I'm not talking about diesels) and in almost no cases can a 5w-30 or even a 0w-30 not do the same job. That's all - it just depends on how rigorous you are being with the definition of "obsolete." Additionally, I can't speak for your province, but here, try buying a 10w-30 synthetic at Canadian Tire. It's a bit of a chore, to say the least. I think they've been listening to Caterham.
Heck, a number of 5w-20 synthetics disappeared from their shelves, too. In many climates, of course, 10w-30 will suffice. For me, though, a 5w-XX is specified, plus the weather justifies it. I have zero concerns about using a 10w-30 in a fair number of conditions, and in an engine calling for 10w-30. I just don't like the idea of changing seasonally, and to me, if an oil isn't good enough for all year usage in an all year vehicle, then it's not going into said vehicle.
Shannow: GM calls 5w-20 obsolete, too.
Their literature recommends 0w-20 for all 5w-20 applications, just like a 5w-30 dexos1 for all previous 10w-30 applications.