What is the best additive for a high mileage engine?

10 Top-Rated Oils and Additives for High-Mileage Vehicles

Valvoline High Mileage with MaxLife Technology Synthetic Blend Motor Oil.
Pennzoil High Mileage Motor Oil.
Slick 50 Recharged High Mileage Treatment.
Gumout Fuel System Cleaner.
Royal Purple High Mileage Synthetic.
Techron Fuel Cleaner.
Mobil Super High Mileage Oil.

What are Slick 50 and other engine oil additives?

Slick 50 (engine oil additives) Slick 50 and other engine oil additives supposedly reduce engine wear and increase fuel efficiency. You may have heard the commercial or seen the ad:

Which is Slick 50 high mileage engine treatment?

Slick 50 Recharged High Mileage Engine Treatment propriety ZDDP formulation is built from a base of fully formulated multi-grade motor oil that meets ILSAC GF5 motor oil specifications for high mileage engines.

Is the Slick 50 really a good product?

I can remember the advertising at the time, they took a car treated with Slick 50 for a lap round some track without any oil in it and it was fine. They said it stuck teflon to the moving parts (I think) making them slippy, which increased efficiency and made an engine quiet.

Is there PTFE in Slick 50 supercharged engine treatment?

[new] According to theSlick 50 website, Slick 50® Supercharged Synthetic Engine Treatment no longer contains PTFE. Slick 50® Recharged High Mileage Engine Treatment contains a small amount of PTFE. [/new] PTFE is a solid which is added to engine oil and coats the moving parts of the engine.

Slick 50 (engine oil additives) Slick 50 and other engine oil additives supposedly reduce engine wear and increase fuel efficiency. You may have heard the commercial or seen the ad:

How does Amazon Slick 50 prevent oil leaks?

Revitalizes seals to help stop oil leaks and prevent them from ever occuring Powerful detergents to remove and prevent oil sludge, use during your next oil change or between changes to replace lost additive content

What is the best additive for a high mileage engine?