Originally Posted by KrisZ
So your deduction is that a 5w20 dexos oil will cause damage?
Not me, GM. I didn't write the manual. The subject is what the owners manual says, and that matters to the GM Warranty Dept. I myself think that a 5w20 could possibly cause engine damage on a very cold day, given the tight clearances in GM engines since 2012. Also the associated problems with bypass events washing junk into the bearings during cold starts with 5w20 oil. Less likely with 0w20 oil. I see what GM engineers are doing, they protect cold starts.
Read the part about tighter clearances, and the associated pressure spike:
https://www.corvetteforum.com/forum...f48e-oil-filter-instead-of-pf64-pf48.pdf
So your deduction is that a 5w20 dexos oil will cause damage?
Not me, GM. I didn't write the manual. The subject is what the owners manual says, and that matters to the GM Warranty Dept. I myself think that a 5w20 could possibly cause engine damage on a very cold day, given the tight clearances in GM engines since 2012. Also the associated problems with bypass events washing junk into the bearings during cold starts with 5w20 oil. Less likely with 0w20 oil. I see what GM engineers are doing, they protect cold starts.
Read the part about tighter clearances, and the associated pressure spike:
https://www.corvetteforum.com/forum...f48e-oil-filter-instead-of-pf64-pf48.pdf