15w-40 or 5w-30 ?

[arthr31]

Mike, thanks for the information. A follow-up question: do I need to be concerned with using synthetic oil in an older engine? I was told, by a mechanic, like 15+ yrs ago, that synthetics might erode gaskets and such. And, same guy said that once i went with synthetic, I would never be able to use regular oil again because the synthetic properties have coated the engine.. Is this hogwash?? Thanks again, -Art

 

[gsxr1100]

You can go back and forth anytime you want. No mixed could be an issue, but many times not. If you get leaks, the dino was covering it up and the synthetic cleaned out the "band aides". So the syntehtic will cause leaks, but the leaks were always there.

Many years ago they (synthetics) did not have proper seal swealing agents. That has been fixed many years ago.

 

[arthr31]

Thanks again, Mike. I guess I'll be looking at synthetics for this seasons oil changes... -art

 

[gsxr1100]

I am not saying it is the best oil for every app (it is) but based on temps in MA, that vary from –12 below F to over 100 F (for me) I think it is your best bet here.

The last thing I want or need to worry about is if some oil is going to be a block of mud at –12 below F. All I want to do it turn the key and go. 99% of din's will not be able to be used here. Nevermind in hills towns or more North.