The 3.6 is not known to mechanically shear(break down) oil except in one case, and that is if one is a chronic short tripper specially in the winter. Fuel is what thins out the oil. Other than that no shearing happens. You should know better. Or you are just used to Blackstone reports that 99%...
The thickest 0W-20 is 9.0 cSt at 212 degree F, most 0W-20s are 8.2-8.4. Now imagine that at 240 degrees F, now we are talking 0w-16 or lower. 0W-20 is fine for daily driving, not for offroading in the desert heat or towing in heat.
Thick oil doesn't hurt anything, it is the other way around. When your oil temp reaches 230 and 240 degrees on the trail, you don't want XW-20 anything there. Again, I welcome you to BITOG.