\nThe following is by my understanding.<\/p>\n
\nWhen I was a kid I had a Honda 50 minibike. My understanding was that it took 10w40 motor oil. I knew some people who interpreted the manual a different way, so used 10w30 with theirs. “That means it acts like 10 weight when it’s cold, but 30 weight when it’s hot,” somebody said. Even at age 11, with no hands-on experience with engines, it made sense to me.<\/p>\n
\nDecades later, I drove a (used) sedan that took 10w30 oil. I recall hearing 10w30 mentioned a lot by car people, in connection with their used 70s and 80s cars.<\/p>\n
\nNowadays, the lawn mower I use takes 10w30, but the vehicles we drive, both from the 20-teens, take 5w20. Sometimes I wonder what happened to 10w30, vehicle-wise.<\/p>\n
\nI have realized for awhile that thinner oils go along with smaller tolerances, so the oil can get into the smaller spaces.<\/p>\n
\nYet, another idea I wasn’t thinking of is that a thicker oil is harder for the engine to circulate. Therefore, another reason manufacturers are going to thinner oil is to ease its motion throughout the engine.<\/p>\n
\nInteresting, eh?<\/p>\n
\nSource:<\/p>\n
classichonda50saustralia.com.au<\/a><\/p>\n