Search the maintenance section at the top for seafoam. Lots of posts on this. Also FYI, if you have questions that are non-roadmaster specific, then it would probably be better to ask the questions in the appropriate section of the forum (IE supsension, maintenance, wheels/tires etc). You'll get more responses that way. Just trying to help.
From reading other posts on here, people have advised against using it as an oil additive and against switching from regular oil to a synthetic oil because it may clear out some of the gunk that is actually helping to seal against leaks.
Having said that, I used it in my lower miles car that has only run Mobile 1. But won't use it my other car for the above reason.