Agree with Izaac Zachary.
Project Farm is one of my favorite channels. They do a lot of objective tests.
^ His test is with 30 weight conventional oil, so not exactly a high bar. Slick 50 claimed it would greatly reduce engine temperature, and that an engine would run for a much longer time even if all of the oil was drained, because it sticks to the internal parts and remains effective as a lubricant.
He ran two engines, one with Slick 50 @ 20%, and one with just 30 weight as a control.
Result:
The engine with Slick 50 reduced cylinder head and crank case temperature slightly compared with a plain 30 weight oil. However, once the lubricant was removed, the Slick 50 treated engine seized waaaay sooner, at around 2 minutes vs 7 minutes for straight oil.
I wouldn't mind seeing a temperature test using something like a modern 0w30 full synthetic.
His commentary:
"Guys I used to use Slick 50. I really liked watching their commercials 25 years ago. I was sortof a believer. I spent a lot of money on Slick 50 trying to preserve my engines. Maybe I'm missing the point. Maybe this product can do something I don't realize, but quite frankly it gave up far before the engine with regular motor oil did, and that's very discouraging. Is there a product that's better than Slick 50, that's better than conventional oil, that truly can stick to engine parts and make make the engine last longer? If there is, please put it in the comments. I read your comments. Please don't feel this video is wasteful. I'm truly interested in learning if the claims manufacturers make are accurate so I try to run these tests as fairly as possible to see what kind of results we get."