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Should You Use a Diesel Fuel Additive?

Have a diesel-powered car? Here's why a good diesel fuel additive is necessary to keep your engine running smoothly.

If you’re a new diesel owner, congratulations! You can expect high fuel economy, hundreds of thousands of miles of life from your engine and tremendous reliability. Especially if you use a diesel fuel additive.

An Additive? Why?

I can hear the, “Wait, what?” already. But just pumping diesel fuel into the tank isn’t enough. A diesel fuel additive is a wise investment in the short- and long-term operation of your diesel car, truck or SUV.

Doesn’t Diesel Burn Off Better Than Gasoline?Diesel fuel pump

Diesel fuel does burn more cleanly and completely than gasoline, but that doesn’t mean it’s immaculate. The combustion process still results in some residues that can turn into buildups. For example, fuel injectors are some of the most critical components in a diesel engine, delivering fuel to compressed and heated air to cause the combustion. Deposits can clog those injectors, restricting the fuel delivery and giving you reduced performance. Allow that to continue and you’re likely to have to foot the bill for new injectors.

Your filters can clog with gum, varnish and debris, too, meaning more frequent replacement and a higher maintenance costs — and repair costs if you neglect to change them.

Winter Is Coming (Every Year)

The right diesel fuel additive can help prevent all those things, as well as improve your engine’s ability to start in cold weather. Look for an anti-gel diesel fuel conditioner.

Diesel fuel has paraffin in it. It’s in liquid form, but at 32 degrees Fahrenheit, it starts to crystallize. Between 10 and 15 degrees Fahrenheit, it turns to gel, clogging the filters and the fuel tank itself. Anti-gel additive, like coolant in your radiator, lowers the gelling point, and in the right mixture, will reduce it to a temperature that’s unlikely to occur on the coldest night.

While today’s low-sulfur diesel may be good for the environment, the chemical process used to remove the sulfur and replace it with hydrogen also takes out much of the lubricating property of diesel fuel. To reduce premature engine wear, it needs to be put back, and a diesel fuel additive will do just that.

Bottom line, a good anti-gel diesel additive will save you money and get you a lot more trouble-free miles from your diesel vehicle.

Check out all the chemical products available on NAPA Online or trust one of our 17,000 NAPA AutoCare locations for routine maintenance and repairs. For more information on diesel fuel additives, chat with a knowledgeable expert at your local NAPA AUTO PARTS store.

Photo courtesy of Flickr.

Mike Hagerty View All

Mike Hagerty is an automotive journalist whose work has been featured on radio, TV, in print and online since 1997. He's the Publisher and Editor of, and contributes car reviews to the Los Altos Town Crier and Previous outlets have included KFBK and in Sacramento, California, the ABC television affiliates and Hearst-Argyle and Emmis radio stations in Phoenix, Arizona; AAA magazines for Arizona, Oklahoma, Northwest Ohio, South Dakota and the Mountain West and

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