This is the common sentiment in the vintage Porsche forums I belong to...It's not a good idea to cross pollinate. If you have been using traditional oil..stick with it.

I use Deere 45-15 on my pickup and trail blazer. It happens whenever I get a little time. I would say it averages 4-7 K. My oil light rarely comes on.

I do put the 5-30 in the wife's car. And that usually happens about 4 K

Oh yeah. It's because the Deere oil is WAAAAAAY cheaper because I get it in bulk. That and my tractors work way harder than my pickup so I'm not worried about it.

Brought that up with a dealer one day when I took it in for other routine maintenance... the manual says "at least once per year" or when the computer says so, a lot of people say 5k or even 10k is fine these days, the computer says I'm at 60% life.... and they still tried to convince me that it's strictly every 3k, of course so I could have them do it for some stupid price.

And even then, 3k is so ingrained, I kind of felt bad waiting for 5k, and even then the computer's still at like 40% remaining.

New car is 15k or one year, and I'll definitely hit one year first.

That is ridiculous. Almost half the oil you can buy at any store is a dino/synthetic blend.

Dino oil is largely alkane-based and synthetic is largely composed of alkenes and carboxylic acid derivatives. The compounds do not disturb one another in any way.

Essentially everything else you put in your car is also a mixture of various chemicals rather than a pure compound.

It's not ridiculous....I get my advice from people who race these cars and have 20 years of experience with repairing them. Many people have experienced oil leaks after switching to full synthetic. Then again I use really expensive dino for my car...20w/50 that you cant get from AutoZone. You do understand that my model is 25 years old. For whatever reason..the seals dont respond well to it...could be that my model requires such a heavy oil.