This weekend, I changed the oil in the TCH (Camry Hybrid). The manual calls for 0w-20 or 5w-20, with no other alternate grades specified. But notice the tantalizing language shown underlined in red in the photo, below. Relying upon this, I decided that I would try a fill of "old" M0428... green GC, which is over 12 cSt. I had just finished my second run of PP 0w-20. Not surprisingly, coming off the mid-8 cSt PP and going to the thick GC, I noticed an immediate drop in mpgs, as displayed by the computer. Typically, in the mixed highway and city driving I do, I'd see 36-37 mpgs indicated on the display. So far this week, driving pattern the same, temps somewhat hotter than the last few months, I have not been able to coax the displayed mpgs above 34.5. That's pretty hard to overlook! Oh yeah, subjectively, the engine is running fine. I do not notice any of the sluggishness that others switching "thin oil" cars to GC have noted in past years. Nor are there any undue or scary noises when it's cold. Go figure. Comments?