The previous owner of my 2005 5.3L Chevy truck added a product called 'friction free 3000' to the crankcase at every oil change from 12,000 miles. The shop where he had all his service work done gave me the service history print outs from 12,000 miles to 162,000 miles, the mileage on the truck when I bought it in January of 2014. I did a search and could only come up with a few suspect sites and questionable testimonials. It's sold through Market America and appears to be a pyramid scheme type of marketing strategy. The shop owner sells it and offers it to his customers as an optional additive when he services a customers vehicles...oil changes. After alot of reading, here and a few other sites, I decided to use the LM Ceratec treatment followed with the LM Mos2 in the trucks engine since the 'friction free 3000' didn't seem to do any harm to the engine. I currently have the Ceratec in the engine and plan on running the OLM through one cycle and then start using the Mos2 at every oil change up to 30,000 miles and then rinse and repeat. The truck currently has 168,000 miles and runs quiet and smooth with no oil consumption between changes. I don't recall reading as to whether LM Ceratec or LM Mos2 causes any harm to an engine. Sorry for the long post but my question is....at what point should I expect my engine to start consuming oil, running rough, smoking on start up, sludging, pecking, knocking and eventually seizing? Thanks