I use 10W30 whatever is on sale and change every 3000 miles which is about every 9 months. 45,000 miles no significant compression loss on leak down test. Went through a period of
synthetic oil but still changes every 3000 miles. Waste of money and the thin
oil seems to seep out on my garage floor. Unless you race a lot, just be kind to your motor and give it new
oil....frequently. And check it a lot.
AZ Bob