Excessive exhaust smoke in older or high mileage vehicles is often caused by burning engine oil. Friction and metal-to-metal contact will eventually wear parts creating gaps between the cylinder walls, piston rings, and valve guide seals. Oil burning and smoking can occur when oil seeps through these gaps into the combustion chamber and is burned along with the fuel. Silverhook Stop Smoke Oil Treatment enhances oil viscosity, providing a thick barrier to help plug these gaps which in turn reduces exhaust smoke.