Wednesday, September 27, 2023


RV Consumer Support: Fuel-saving devices – Are they “snake oil”?

By Russ and Tiña De Maris
If you recall that infamous scene from “Blazing Saddles,” you know that there’s a lot of gas floating around these days. Some of the hottest air in the marketplace is on equipment and additives “guaranteed to help you save at the gas pump.” Yep, those highly touted fuel-saving devices.

Myriads of “gas-saving” devices

Add-on devices to modify your motorhome or tow vehicle “work” in many ways. Over the years, we’ve tried several. There’s the “stick this in your air cleaner” device. It will somehow change the air flow, dramatically increasing the burn efficiency. Another: Add a little water! A small reservoir of water is placed under the hood and plumbed into the intakes. The water is atomized and, hey, presto! This “‘steam” expands in your cylinders, giving you more boost. Then there were magnet assemblies placed over your fuel line. The story here is that fuel molecules are clustered and the magnetic field breaks up the clusters, resulting in better burn efficiency. When it comes to fuel-saving devices, we’ve seen tons.

“Snake oil” claims

It’s like “snake oil” for your vehicle. How much will really save you money? The answer is “not much.” Be skeptical of the following kinds of advertising claims:

“This gas-saving product improves fuel economy by 20 percent.” Claims usually tout savings ranging from 12 to 25 percent. However, the Environmental Protection Agency (EPA) has evaluated or tested more than 100 alleged fuel-saving devices. They have not found any product that significantly improves gas mileage. In fact, some “gas-saving” products may damage a vehicle’s engine or cause substantial increases in exhaust emissions.

“After installing your product on my car, I got an extra four miles per gallon.” Many ads feature glowing testimonials by satisfied customers. Yet, few consumers have the ability or the equipment to test for precise changes in gas mileage after installing a gas-saving product. Maybe we should farm this out to Mike Sokol, the guy that loves to build test equipment for everything! Hey, Mike?

So how do we explain the claims?

Many variables affect fuel consumption, including traffic, road and weather conditions, and the car’s condition. For example, one consumer sent a letter to a company praising its “gas-saving” product. At the time the product was installed, however, the consumer also had received a complete engine tuneup – a fact not mentioned in the letter. The entire increase in gas mileage attributed to the “gas-saving” product may well have been the result of the tuneup alone. But from the ad, other consumers could not have known.

“This gas-saving device is approved by the Federal government.” No government agency endorses fuel-saving products for cars. The most that can be claimed in advertising is that the EPA has reached certain conclusions about possible gas savings by testing the product or by evaluating the manufacturer’s own test data. If the seller claims that its product has been evaluated by the EPA, ask for a copy of the EPA report. Alternatively, check for information. In some instances, false claims of EPA testing or approval have been made.

To date, nobody has been able to invent a truly “free lunch.” In fact, publisher Popular Mechanics took these and many other “fuel-saving devices” and put them to the test. They used laboratory equipment to do scientific tests to find ut the truth about enhanced claims. In all cases, there were no increases in fuel economy, and, in some, add-on devices actually decreased fuel efficiency. Check out their findings here.

One sure-fire way of saving fuel

If you really want to save money on fuel, skip the “add-on” fuel-saving devices. One of the best fuel-saving devices you can buy is a good, reliable tire pressure gauge. Use it regularly and keep your tires at recommended levels and you truly will save fuel. How much? Uncle Sam’s fuel economy whizzes say, “You can improve your gas mileage by 0.6% on average – up to 3% in some cases. How? By keeping your tires inflated to the proper pressure. Under-inflated tires can lower gas mileage by about 0.2% for every 1 psi drop in the average pressure of all tires.”

How about you? Are there other products you think are just “hokum” or pure bunk? Let us know by using the form below. Enter “phony products” in the subject line.

Click or drag a file to this area to upload.

Other stories by Russ and Tiña De Maris


Russ and Tiña De Maris
Russ and Tiña De Maris
Russ and Tiña went from childhood tent camping to RVing in the 1980s when the ground got too hard. They've been tutored in the ways of RVing (and RV repair) by a series of rigs, from truck campers, to a fifth-wheel, and several travel trailers. In addition to writing scores of articles on RVing topics, they've also taught college classes for folks new to RVing. They authored the book, RV Boondocking Basics.


  1. Ok I’ve tried several snake oil devices which never worked, now I’ve got a device on my 2018 Nissan Frontier, which are not known to be fuel efficient. Prior to this the truck was getting 12.6-13.8 mpg, I tried one of those $39.95 chips that plug into the OBD port, it increased mpg to 15-16 but like most Made in China products it died 4 months later. Doing research I found a company in GA by the name of Thornton selling similar devices except these come with a guarantee. They sell 3 different levels, $69,79,and $89, they’re not advertised as fuel savers but power gains which requires premium gas, but mpg is a side effect of power gains. I wasn’t interested in the power but the economy. I ordered the $89.95 unit because it said possible 4-6 mpg improvement. At todays prices I’m not buying premium but I’m getting 16 around town and we just returned from FL where I averaged 19.4-20.3 mpg driving 74 mph. I don’t think this is snake oil.

  2. Synthetic oil will help in snow country with start up wear and tear and help a little with mileage. The other fuel saver is a shoe-less right foot! Many years ago, some oil company was testing their gas product for mileage – coast to coast. The drivers had to drive with a raw egg between their foot and the pedal! (That’s a normal everyday practice, right?)

    • I remember a Shell Gasoline TV commercial from when I was about 6-7 yrs old. Believe it or not even that long ago… I’m 68, it was to tell you how to improve your fuel economy. YES, it showed that to prove their fuel “blend” would get you better mileage, a driver was shown with the egg under the accelerator pedal and how gently he pushed to keep from breaking it. Of course, they said that this was the only way to get better mileage than buy using their “blend”. I’m thinking you saw the same commercial, yes?

  3. If any of these so-called fuel saving devices actually worked don’t you think the manufacturers would be putting them on the vehicles to help with their EPA results?

    • Don’t know about now but back during the 70s gas crunch additives promised to boost mileage by 2-3 miles per gallon. Don’t know if they worked on not but when you did the math the cost of the additive was the same the same or more than if you bought a couple more gallons of gas. Most likely the same would hold true for diesel


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