Two generally highly rated engine oil additives are STP oil treatment and Lucas oil stabilizer. While these additives garner mostly positive reviews, the efficacy of engine oil additives in general is often questioned. In some cases, the Federal Trade Commission has banned manufacturers of oil additives from making what were deemed false claims about their products. Additives whose manufacturers were accused of making false claims include Slick 50, DuraLube, MotorUp and FuelMAX.
Most oil treatments are designed to inhibit rust, increase viscosity or prevent sludge from building up with the ultimate goal of reducing engine wear. Most synthetic oils on the market already contain additives designed to serve the same purposes as common engine oil additives. In general, using the correct oil weight and changing a car's oil and oil filter regularly eliminate the need for oil additives. That being said, there has long been dispute as to whether oil additives work, and many sources still argue vehemently that they do. There are also cases, such as in professional racing, where certain types of oil additives are necessary to allow the car to accelerate quickly and to reach high speeds without creating the engine issues that racing may normally cause.