Originally Posted by Taken from Tech Letters by Scott Parkhurst

Engine Masters magazine; from the editors of Hot Rodding
QI've been intrigued by engine coatings since I first read about them on your pages. While all I hear is good, I'm wondering how well these can really work and what are the long-term effects of running coated engine parts? At what point do they begin to shed, or are they truly good for the life of the engine?
It seems to me the only engines running them are race pieces, which are serviced regularly, and this allows the coatings to be checked or re-done often. I find it hard to believe a coating could survive life on bearings, pistons, or any other "metal-to-metal" situation.
Please advise me on this. I build both race and street engines at my shop, and if coatings are all you say they are, maybe I need to start adding them to all the engines I build.
PS. I love the Engine Masters magazine!
P.Short
From the internet

AThe latest engine coatings are durable enough to last the life of the engine. In the metal-to-metal contact situations you refer to, some of the coatings may wear, but the manufacturers tell me the coating is still there, even though the coating may be so thin or even embedded into the metal, so it cannot be seen with a naked eye. But, the protection is still there, and so are the benefits.
Coatings serve specific purposes depending upon what kind of coating it is and where it's been applied. Also, the application technique is important for long life. It is absolutely imperative the manufacturer's instructions be followed precisely so the coating has a chance at living in the harsh environment inside the engine.
Overall, we've seen nothing negative with regard to properly-applied, professional-level internal engine coatings, and in fact, we've discovered several OEM manufactureres are using coatings in new, production-line engines. If they had any long-term durability downsides, we know this could never happen.
Coatings offer the ability to reduce friction and control temperatures inside your engine. If these issues are important enough to justify the expense of having parts coated, what's stopping you?