Trying to figure out which type of oil to run in older stuff has always confused me since API ratings have changed over 40 years. I have a set of Chris craft marine 454 engines and the original manual says to run SAE 30 or 10W-40 with an API SE. I see Volvo makes a 10W-40 that has an API SJ but I don’t know if that’s appropriate or not. I’ve heard of people running valvoline vr1 30 weight for the high zinc count in it. There’s obviously the people that run 15w40 diesel oil and merc 25W40 and apparently that works for them. I get all these numbers and letters in my head and then I get all sorts of confused so any help from what you guys have to say would be appreciated.
Thank you
-Grant Litynski
Thanks Tom! I order the test kits this morning. We shall see...