Do Oil Additives Improve Engine Performance?


Question: I have been reading with interest advertisements about friction-reducing chemicals that you add to your engine oil, such as Teflon-based additives. The ads make the claim that this will increase acceleration, boost gas mileage, make starting easier and, of course, make engines run better. Is there any truth to these claims?--D.G.

Answer: The appeal of such products is obvious, because what they hold out to the motorist is the solution to major problems in exchange for only a few dollars and the bother of pouring a can of liquid into the engine. In reality, few major problems are solved so easily.

Engine oil additives are among the most common products sold in auto stores. Typically, they make the claim that they will reduce engine friction, boost gasoline mileage and reduce oil consumption.


Seldom do motorists know exactly what they are getting when they buy these additives. One of the few exceptions to that rule is the advertised use of Teflon.

We all know that Teflon is that wonder plastic used on frying pans to keep scrambled eggs and other foods from sticking. Teflon was developed by DuPont, which makes the claim that the substance is the most slippery in the world.

If Teflon can keep eggs from sticking, isn’t it possible that it could also keep engine parts operating with less friction? Unfortunately there is a dearth of scientific evidence to back up such claims.

Of course, DuPont would love to sell as much Teflon as it possibly can. And yet, DuPont makes no claim that Teflon is suitable as a motor oil additive.

In fact, DuPont announced 10 years ago that it would stop selling raw Teflon to formulators of oil additives, but it has since reversed that stand. DuPont does sell the raw product to formulators but makes no claims about its effectiveness.

“We do not endorse that use of Teflon, but we supply it to people who believe in its value,” a company spokeswoman said. “It is not like us supplying Teflon to the cookware industry, where we supply a certification label for Silverstone. We know about that product. We don’t have any expertise in motor oil.”


No major motor oil producer, such as Quaker State, Pennzoil or Valvoline, uses Teflon, the spokeswoman said. Why not? I suppose some people would allege that motor oil companies and the auto industry have conspired to prevent consumers from getting products that would keep their cars running longer.

That’s the sort of wild conspiracy theory that went out with General Motors’ dominance of the car industry, though. Today, we have to accept the fact that the highly competitive motor oil industry is supplying motorists with the best lubricating products their technology can produce.

When you buy a motor oil, it carries a rating established by the American Petroleum Institute, certifying that the oil meets certain qualities for anti-wear, anti-oxidation, detergency and viscosity-index improvement. It is possible that many of the higher-quality substances in after-market additives are already in a high-quality oil.

Another type of common oil additive is a viscosity improver, which typically can add 10 points to the viscosity of your motor oil. For example, it would boost it from a 10W-30 to a 20W-40. But if you wanted a heavier oil, you could simply buy heavier oil.

Finally, if you want better lubrication in your engine, it might make more sense to change the oil in your car more frequently, rather than investing in an additive of unknown quality.