Are Aftermarket Additives All They’re Cracked Up to Be?
I recently got an internet advertisement for an aftermarket oil treatment. The brand is not important, but the concept and presentation speak to many of the conflicting thoughts I have about aftermarket additives, which are often referred to as “snake oil” or “mouse milk.”
I ’m sure many of you, if not all, have seen advertisements for various additives designed to give engine oils and transmission fluids extra performance features, or at least add to the already strong performance of the oil. I think it is of enough interest that I wanted to share some of my thoughts on the subject. The question is: Do aftermarket oil additives actually add to vehicle performance, or is it just hype?
What do aftermarket additives do? First and foremost, they modify viscosity properties. We all know that viscosity is the fundamental oil property of resistance to flow. Lower viscosity means faster flow, which can be a valuable property. However, for older, high-mileage engines, lower viscosity often translates into more oil consumption, often to the point of an oil slick on the garage floor. It used to be that owners of older vehicles went to higher viscosity engine oils to reduce the losses. I can tell you that modern engines like the 3.5-liter V-6 in my Nissan Quest have solved many consumption questions. Using the recommended SAE 5W-30, it is still not consuming excess engine oil, even after 158,000 miles.