oil and engine restorer

i havent changed my oil in over 6 months mobil 1 syntec is the best for a honda engine rite 10w 30?... also i've seen this stuff in a silver can called engine restorer what will that stuff actually do says to add to each oil change does it work? wat it do

it makes the oil thicker so it doesn't leak. Same type of logic why you shouldn't use synthetic oil in an old engine.

it makes the oil thicker so it doesn't leak. Same type of logic why you shouldn't use synthetic oil in an old engine.

why shouldn't you use synthetic oil in an old engine? and how old engine are you talking about?