Yes, but you shouldn't need to, idling on Grand, stuck in traffic with the A/C cranked. I'm learning Schaeffer premium oils work well, I don't no where to get 'em on the westside, but Lee Finke probably does. 602-493-3700
I looked into this a few years ago, checking the oil clearances in the engines didnt find anything tighter than the specs for the last 30 years on even the 5w20 engines.
Some discussions elsewhere concluded that the light oil was to reduce the drag of the pump. I can imagine the extra power it takes to move the heavier oil until it warms up. I have been using 15w40 in them for years without problems
It could cause the mighty "VOID" stamp to fall on your warrenty though.