Any opinions on oil additives like Prolong*, Slick 50* etc. I used a cheap one ($5/qt) and my engine runs like new after 109,000 mi, but I think it’s mostly a psycological thing.
[b]These products are called “Snakeoil”.
They make claims of one form or another in order to sell the product. But are unable to produce scientific/engineering test data that supports those claims.
The auto manufacturers and the American Petroleum Institute work hand-in-hand in formulating the proper oils for todays engines. And if any of these products actually did what they claimed, you would find the ingredient(s)in todays oils.
Tester[/b]
Tester, I appreciate the insight in your answer. I have seen “scientific evidence” from Prolong* in their commercials, but there’s much doubt as to the validity. I’ll just keep using synthetic blend oil from Motorcraft at $2.19/qt, man.
Many products like this do have a placebo effect.
The only oil additive that I have ever used that actually made a noticeable difference in something was BG, and it was not used in an engine.
I used to commute 160 miles a day to work so I had plenty of opportunity to test things like this, and BG (free samples from a rep) made no difference at all in performance or fuel mileage when used in an engine.
However, I did mix some of it in with the transmission and fork oil in one of my old Harley Davidson motorcycles and it did make a noticeable difference in shifting the transmission (non synchronized, and notoriously clunky) gears and vastly improved the hydraulic fork operation for a smoother ride.
Gave several cans to a friend to use on his HD and he reported the same, so it’s good for something anyway. 
Snake oil. Du Pont does not allow vendors to use the proprietary name “Teflon” in these applications or misapplication as the case may be. Teflon or whatever they call it will be stopped by your oil filter.
Thanks ok4450 for that great story, man. Seems BG Products makes a diff. in Harleys, the trannies and forks anyways. Nice to see you having positive results bud.(Nothing better than makin a Harley run smoother, I had one) I guess if the 5 or 10 bucks makes one think their ENGINE runs smoother, it might be worth it 
The bike in question was a '75 shovelhead dresser. The forks had gotten somewhat stiff (no leaks) and at work one day I figured, what the heck. Dropped an ounce or two into each fork leg and it rode like a cloud on the 80 mile ride home.
The friend’s bike was an '84 Softtail.
My '44 flathead has a spring fork, so no luck there!
Slick 50 allowed it for many years, starting in ~84. It was the big talk among motorheads. I don’t know what the policy is now, I’m sure it’s diff. But, I’m not sure filters would catch PTFE molecules while letting mass volumes of oil through.
Nice bikes ok4450, I had '91 Sportster, beautiful machine. My wife made me sell it when we bought the house. '44 would be well before oil therapy, doh!
In thought…why couldn’t you buy a hundred cases of this stuff, market it as a fork lubricant, have riders try it out, and make it your business, man? It’s something to try out, ok4450.
When it was first out, Slick-50 being the largest seller and advertiser, it did not take long before it was found that the Teflon was causing various problems and was not really helping anything. It was damaging engines.
That is why Teflon does not allow it’s name to be used by these companies when they advertise their product, even thought they claim they have fixed the problem. That is the problem that they said never existed. Yea sure.
There are several arguments against using Teflon…but the biggest argument is the Word Teflon.
When Slick-50 was first introduced they used the name Teflon in their product. Teflon is a trademark name owned by Dupont. When Slick-50 started to get popular Dupont decided to look into this. They knew from their own testing how hard it was to get Teflon to stick to metal. So how was Slick-50 able to do it.
After a year or more of testing Dupont found the Slick-50 product to be nothing but snake oil and didn’t want their name associated with this product. So they forced Slick-50 to REMOVE the name Teflon from their product…That’s why they use PTFE (which is the chemical name for Teflon).
Mike, that was a well-thought-out, well versed reply to my original question. Thanks, man.
Worthless snake oil. The best you can hope for it that it won’t cause damage.
In more than 25 years as a test engineer in a transportation laboratory, I never found any of these products to do any good.
Over a dozen years ago I was wondering whether there was any validity to these products-- especially if they reduced friction and thus improved gas mileage. I’d tried them and couldn’t notice any difference in fuel consumption on my diesel rabbit but it did seem to accelerate faster (which could be a placebo effect).
I got in touch with the fleet manager of a company that operates one of America’s largest fleets of trucks (and is known for extreme thrift in its operations). I asked why they didn’t do a comparison-- put the stuff in some trucks and not others, and track fuel mileage.
He said they did and found no difference.
So I stopped using the stuff.
Shaun Eli
Brain Champagne: Clever Comedy for Smart Minds (sm)
Snake oil, plus in some case the particles do nto stay in suspension and can accumulate in fitlers and oil passages causing more problems
Almost all additives are snake oil and even those that may work are last case scenerios in lieu of a major repair cost
I have a 1996 dodge grand caravan with a 3.3 liter engine and have only used a variety of brand name oils and filters, changing the oil approx. every 5000 miles. it has 220,000 miles and still runs strong. unfortunately I can’t say the same for the transmission which needed rebuilding at 140,000 miles! good luck
Teflon doesn’t melt until it gets to 660F. I don’t think the oil gets that hot. It gets much hotter in the combustin chanber - hot enough to decompose the Teflon. Either way, it won’t provide any beneficial effect.
109,000 miles and runs like new is not at all unusual now. I expect that there is not enough Teflon in these products to completely plug your oil filter. Possibly it is more correct to say that your engine runs like new in spite of the Teflon additive.