Why acetone damages cars (and other answers)

Herb Weisbaum • Profile • E-mail

With the price of gasoline hovering near record levels, many readers have questions about how they can shave off a few cents on their bill.

From hybrids to fuel additives to the psychological reasons for gas pricing at the pump, my readers weigh in.

As the summer goes on, I'm sure you'll have even more questions. I won't be able to answer everybody, but send me your questions and I may address them in a later column.

I’ve heard of an unconventional way to increase gas mileage by up to 25 percent - adding 1 to 3 ounces of acetone to every 10 gallons of gas. Is this true?
— Chad in Seattle, Wash.

No. Acetone won’t significantly boost your mileage and could damage your engine.

Acetone is a powerful solvent that’s used as paint thinner and nail polish remover, so it’s very corrosive. That’s why many automakers specifically warn against using it.

On their Car Talk Web site, NPR’s Tom and Ray Magliozzi make it very clear that acetone “does absolutely nothing” to increase gas mileage.

“It’s bo-o-o-gus,” Tom writes. “Don’t put acetone in your gas tank.”

While the acetone is in your fuel system, he says, “it’ll be eagerly dissolving all of your rubber components … like gaskets and O-rings.”

But what about all the people on the Web who say they’ve used acetone and seen their mileage skyrocket?

There’s no way you can judge fuel efficiency on your own by just driving around. Because of varying conditions – weather, road surface and traffic, your mileage varies normally. The only way to know if something really boosts mileage is to run controlled scientific tests.

Over the years, the Environmental Protection Agency has evaluated or tested more than 100 products that promised to save gasoline. It did not find a single one that significantly improved mileage, although some did substantially increase exhaust emissions.

Still think you want to give acetone a try? Just remember this – using it could void you warranty. And don’t spill any on your car; it could remove the paint!

Tom and Ray on acetone

We own older models of the Chevrolet Tahoe and Cavalier. How will these vehicles run on E85?
— Curtis H. in Glencoe, Ark.

Hold on! You can’t use E85 in your Cavalier. It could ruin the engine. And you can only use it in the Tahoe if it’s specifically made to burn E85.

E85 is a blend of gasoline and up to 85% ethanol alcohol. It can only be used in a “flexible fuel vehicle” that’s designed to run on gasoline or E85. The engines and fuel systems in these vehicles have been modified to handle the higher alcohol content in the E85.

Use E85 in a regular gasoline-powered vehicle and that alcohol can eat away at the engine’s rubber and plastic parts.

The Chevy Tahoe has been available in a flexible fuel version since 2002. The Cavalier was never designed for E85.

Dozens of vehicles from various automakers now come in flex-fuel versions. They look the same as their gasoline-powered twins, so you could have one and not even know it. To find out, look for a sticker on the car’s fuel filler door or check the owner’s manual.

The U.S. Department of Energy says flex-fuel vehicles “typically get about 20 – 30% fewer miles per gallon when fueled with E85.” That’s because a gallon of ethanol contains less energy than a gallon of gasoline.

Flex-Fuel vehicles

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