Oil thickeners (and products that swell seals), and thick oil, will quiet a motor down (soundwise) it can slow the smoking from burning oils, they also can rapidly accelerate vital parts wearing because they are simply too thick and do not flow readily (especially on start-up, and also note how your piston wrist pins get oiled). Those products hide the symptoms , they "mask" the problems.
You do not get something for nothing with those products, no such thing as a free lunch, sorry no miraculous cure in a tin can.
If your motor doesn't run right (smokes, knocks) etc with a good grade 10W-30 oil (10W good for lube on start-up) then like Mr. Lang says your just putting on a band-aid ... but one that could worsen the overall wear.
