I am fascinated at how scared people are at using these relatively thin oils, that are barely even available in Australia. I am in Melbourne, 5 days for 45 degree ^c a year, hot dry summers, winters anywhere from 1 degree^c cold mornings in winter to 14 degree days. Canberra and Tasmania would have to be some of our coldest areas apart from the Alpine regions (sparesly populated), but thousands go skiing etc.
What i am trying to say apart from talking [censored] is 5w30 would have to be a rare oil, Castrol Edge most commonly used as its cheap for a synthetic, 10w30 the next, but 10w40 to 20w50 would have to be the most common oil used. Manufacturer work shops doing the same, sometimes deviating from the book.
America seems to use thinner oils than Europe where its colder most of the time. Ambient,Shambient, it seems its more of a culture now in the U.S to use thin oils than anything else. 25w60 oils starts up fine on a cold morning, the one i used a group 3 was made to still flow at -20 degrees^c. Yes it feels heavy on startup on a very cold morning, but few seconds later and its idling well, whenever you lift the oil filler there is always a nice film of oil on it, came with a free oil test, tested at 10,000k's had another approx 10,000k's of life left in it.
Pushrod engines can go pretty thick, overhead cams 10w50 would be the thickest you would use in most circumstances.
Corolla 06 hand book says use 5w30 for best economy, Toyota put 20w50 in it ??? Book says to also use 15w40 or 20w50. Toyota go for the highest as it seems to keep them quieter. Obviously it does not kill the engine if they use it.
