I have used it. I can't say if it is of benefit or not. I used it in my avalanche prior to towing. In a light high reving engine, i don't know if there is benefit. I have not heard of harm from this product. It does seem slow to settle out and does go back into suspenstion easily, at least from my observations in a clear oil bottle in my garage over a month. My main concern is wether you could get deposits in between the 1st and second rings , especially in newer engines where the ring land is up high on the piston.