Last month I finally got why old school guys swear by straight weight oil

I've been running 15w-40 in everything for years, but last month a retired fleet mechanic in Tulsa said I was wasting money on a 6.0 Powerstroke that's already got 280k on it. He showed me how much blowby was getting past the rings with multigrade and said straight 30 weight would seal it better. Has anyone else switched to straight weight on a high mile engine and seen a difference?

2 comments

2 Comments

betty_shah3d ago

Dunno man seems like a lot of fuss over some blowby... if the truck still runs fine and doesn't smoke like a chimney maybe just leave it be.

calebrivera3d ago

Betty's out here using common sense when the rest of us are ready to rebuild an entire engine over a few drops of oil. Pretty soon someone's gonna tell me I should replace my whole transmission just because it makes a weird noise once in a while. If the truck's still pulling a trailer and not leaving a cloud big enough to hide from the cops, I say just top off the oil and call it a day. Half the time people dig into these things they end up with a dozen new problems anyway.