[QUOTE=Craig]I didn't know they had a 10W40 synthetic?

http://www.mobil1.com/USA-English/MotorOil/Oils/Mobil_1.aspx

I was looking at the oil section in the local Wal-Mart (in Canada), and I noticed that Mobil 1 15W50 is no longer available, and appears to have been replaced by Mobil 1 5W50 ! This oil does not appear in the Mobil 1 website. Have any of you seen this oil in the US? Could it be a Canada-only formulation?

I'm concerned that a 5 weight oil will not be viscous enough for summer starts. Perhaps I'll have to switch to Delvac.