Auto-Rx is not an additive. It is a long(er)-term cleaner, unlike Rislone products, which are, for the most part, decidedly more of a short-term (leave them in for a long while at your own risk) additive/flush/cleaner. And I'm not flaming Rislone products as I have used them in the past prior to oil changes on used vehicles I have encountered which exhibited "less than MY expectations of preventative maintenance" to my satisfaction... then.
In short, and IMHO, the Auto-Rx product is one that works as it is presented to work.
I have finished my initial 800 mile Auto-Rx treatment (I used the filter & oil that was in the 420SEL with only 1.5K miles on the oil for the 1st 150 or so miles and then put in a new filter for the remaining 650 miles) cutting open both filters when removed.
No real indication of sludge (didn't expect any with Pennzoil LongLife 15W-40 and 5K changes) but definite capture of small amounts of fine, metalic/carboniferous grit in filter folds. Oil was markedly darker @ under 2,500 miles of use than it was previously at 5K intervals. Metal surfaces visable are clean & shiney: almost look polished. This includes cam lobes, metal on cap and oil dipstick, etc.
Have used this in my 100+K SVX and it is in my 460 Ford as we speak. Also has been used in another 420SEL (neighbor across the street's '88: done with 1st treatment, waiting to get another 2,250 miles on recent oil & filter change for 2nd 750-800 mile application, just like mine) and there is another high mile 460 Ford truck 1st application going on also.
Can't imagine how being cleaner internally can't be beneficial to lubrication & operation of the engine. Waiting to see what comes out of the filters on the 460's & what the oil looks like.
