Well, if there's naptha in it, it probably does get past the rings.  But whoever said these additives were good for anything other than the seller's profit margin?  Most auto makers recommend against adding anything other gasoline to the fuel, and anything other than motor oil to the oil.  VW does say in the owner's manual to use gasoline with engine cleaning additives, but does not say what those might be, and to contact the dealer for advice concerning proper additives to use.

there are lots of oils on the market that are supposed to be beneficial when used in conjunction with regular oils in old or worn engines.  Most of these are just thick oils.  If they are helpful, why not just use a thicker oil to start with, which has other good properties?  If gasoline additives sold in a bottle are so good, why not get gasoline with those things already in it?

---- Edward Maglott <emaglott3@GMAIL.COM> wrote:
> I've also heard that techron was the only injector cleaner that did anything
> for years.  I have used it occasionally on my several VWs over the years.  I
> once even got the MSDS for it to see what was in it.  I remember Naptha
> being one thing.  I also note the advice and this is what I usually do, to
> put it in the tank when I'm going on a trip and will use the whole tank
> pretty quickly, and then change the oil.  Apparently it gets past the rings
> into the engine oil.
>
> All of that may be complete balony.  I am also interested in any scientific
> studies on the subject if they are found out there.
>
> Edward

--
David McNeely