I do add Slick 50 to my old cars... I've read articles from several different oil companies where they recommend that you do NOT put any additives in your oil because it can upset the "recipe" of additives in their formula and do more harm than good. I don't know, I'm not a chemist. Just passing along what I've read.
I used to work with a guy who drove an old "beater" van around. He didn't care much about it, and had lots of other cars to drive, so it was his test vehicle. He ran Mobil 1 synthetic in it, changing only the filter every 3,000 miles and then topping it off. When he changed his filter he would also take an oil sample to a local tractor place which could analyze the oil. Last i heard he had 27,000 miles on his oil change, and still going strong. As for me, i decided to go with synthetic. It does leak more but it's a small price to pay. I run my synthetic for 6,000 miles and filters for 3,000 miles (could go longer, but i'm too nice to my old car).
Here's what Blackstone Laboratories said about synthetics: Pretty interesting consideing Blackstone has no financial ties to any oil companies. http://www.blackstone-labs.com/
We have not found synthetics do better for most people. Claims that they are better a Strange comment since synthetics are proven to flow better at high and low temperature extremes. But you do have to be careful, some companies that market what they call synthetic oil really sell hybrids made of organic base stock and synthetic additives. These are not true, 100% synthetics and they don't hold up as well as the good stuff.
go to hot rod.com and search for "synthetic oil test" they used royal purple...a fair amount of hp increase with nothing more than a change of fluids to synthetic...I use mobil one...they pioneered the stuff ....so i'll go with the most r&d...been usin it forever
Porsche uses Mobil 1 Porsche uses synthetic in their new cars I don't think they have ring seating problems?:confused: After about a year I started using synthetics and change oil about every 6k on my wifes contour v-6. runs like a top and gets several mpg better than with conventional oil. Honest to goodness. So I started using it my 147,000 mile Mustang 5.0 about 20,000 miles ago and haven't noticed any more oil usage (still very low) and an increase of 10-15 miles per tank of fuel. I'm sold on synthetics.
