A few years ago in Flying magazine I read an abstract of an FAA accident investigation involving an in flight engine failure on a single engine general aviation aircraft.

Analysis indicated that a bearing seized. Further investigation showed that the intersection of two drilled oil passages were partially blocked with PFTE - the active ingredient in Slick 50. The conclusion was that the engine failed as a result of a siezed bearing due to oil starvation because the main oil gallery was blocked.

There's a reason why ALL automotive OEMs specifically recommend AGAINST the use of additives and only recommend motor oils that meet the API service specification and viscosity range for the expected ambient temperature range, which is clearly stated in all owner's manuals as is the recommendation NOT to use addtives.

It's also noteworthy that duPont, the manufacturer of PFTE does not endorse the use of PFTE in engines, and I believe they even refused to sell PFTE to the manufacturer of Slick 50 at one point, but the Slick 50 manfacturer went to court and was able to FORCE duPont to sell them PFTE.

Duke