Going on Vacation? Don’t Forget About Your Car

Fuel stabilizer for car models is essential if you are planning to go away for a long time. Check out our top recommendations!

2020 Ford Puma at a driveway with the owner opening its trunk door
  • Fuel stabilizers are mandatory to protect your car’s tank and engine while you are away
  • They are additives you can simply put in the tank and let mix with the fuel over time
  • Here, we show you our recommendations among the several options available online

June and July are months where we can only think of traveling. The children have time away from school, the Northern hemisphere goes on its delicious summertime, Southern countries present beautiful winter scenery… All we want is to pack our bags and travel. However, we also know that we have responsibilities. Just like we must take care of our work and home duties before leaving, we cannot neglect our car.

In short, cars are built to be used with a certain frequency. If you are planning to be away for over a week, you have to take some precautions to find it in top shape once you return. In this article, we are going to cover its fuel system. While it is important not to keep it totally dry, we must also take care of the fuel we are going to leave there. But there is no need to worry: we are going to show you how to do all that.

Best overall

Star Tron Enzyme fuel stabilizer

Star Tron Enzyme

Great chemical properties, works with many engines, and comes at a high concentration.

Best for Long-term Storage

Sta-Bil Storage fuel stabilizer

Sta-Bil Storage

Similar advantages to the previous one, but with a traditional brand and multiple sizes.

Best for Older Cars

Lucas Oil fuel stabilizer

Lucas Oil Fuel Treatment

If the store is out of both the fuel stabilizers to the left, this is the perfect one to choose.

Woman at a gas station refueling her car

Why do I need a fuel stabilizer?

Let us go step by step. Before leaving the car parked for a long time, you should keep its tank full to keep minimum air volume above it. That is important because air contains water particles which will eventually mix with the fuel. The more water there is, the more likely your car will be to show oxidation through the fuel line because the engine’s metallic parts are not prepared to interact with a high amount of water.

Sadly, that is not the end of it. Fuel has an expiration date; it will degrade regardless of how much water it contains. That means it will lose its combustion properties and may even decompose. Many regions use a blend of gasoline and ethanol, which respectively repels and attracts water. Over time, that difference can separate those elements and, later, feed the engine with pure amounts of each. That is just as harmful.

Man at a gas station refueling his car

How can fuel stabilizers help?

They are pour-in additives that slow down that oxidation process. In other words, you simply add them to the tank before leaving the car. They are a mix of antioxidant and lubricant substances that will gradually bond with fuel molecules. As a result, you can stall oxidation and the formation of ice during winter. And, as you can imagine, there are countless fuel stabilizers available in the market at a wide range of prices.

We are talking about a chemical product, so there are many variables involved. Each fuel stabilizer has its own selection of ingredients. Each ingredient comes at a specific proportion. Fuel quality varies a lot from case to case. Some regions have higher humidity than others. And some people will leave their car parked for longer than others. This is why we have brought you this handy list of recommended fuel stabilizers.

Shell gas station at night

What is the best fuel stabilizer?

As usual, we are going to compile our recommendations in three ways. First of all, you are going to find a table below with an overview of all the fuel stabilizers we have selected. Then, the article moves on to the individual reviews of all the products along with their pros and cons. Lastly, we show you our conclusions, that is, what product we recommend above all the others and our honorable mention. I hope you enjoy!

Fuel stabilizerDosageVolumesBuy it now!
Iso-Heet Water Remover1 oz to 1.66 gallon12 ozCheck price!
Lucas Oil Fuel Treatment1 oz to 1 gallonMultipleCheck price!
Royal Purple 117221 oz to 1 gallon20 ozCheck price!
Sta-Bil Storage1 oz to 2.5 gallonsMultipleCheck price!
Star Tron Enzyme1 oz to 4 gallons8 ozCheck price!
STP Ultra 5-in-11 oz to 3 gallons12 ozCheck price!

Best overall: Star Tron Enzyme

Star Tron Enzyme fuel stabilizer

This fuel stabilizer uses proprietary enzymes to break down water molecules. This way, it prevents phase dispersion and slows down corrosion at the same time. You may also like to know it comes concentrated, which means 8 oz treats 48 gallons, and it also treats fuel for other types of vehicles. Star Tron claims it is capable of protecting fuel for two years, rejuvenating old fuel, and f cleaning the entire delivery system.

It is important to know that the product works on ethanol, so it will not be as effective with pure gasoline. You also have to pay attention if your car has a diesel engine: Star Tron has a different product for those. Another drawback is being one of the most expensive fuel stabilizers here, even though its concentration offsets that problem. Besides all that, it might be difficult to measure the right amount using its bottle.


Concentrated formula treats up to 48 gallons
Protects ethanol-based fuel for up to two years
Works with many two and four-stroke engines


Diesel engines require a different fuel stabilizer
One of the most expensive products in this list
There are complaints of difficult measurements

Best for Long-term Storage: Sta-Bil Storage

Sta-Bil Storage fuel stabilizer

Sta-Bil is one of the most experienced manufacturers in this segment with over 60 years of activity. Its fuel stabilizer protects gasoline for two years by removing water from it. That is important to slow down phase separation and prevent corrosion. You can use this product in any two or four-stroke engine, which makes it appropriate for many vehicles. Its price and concentration make it quite affordable in this segment.

Now, if you make us talk about drawbacks, we will start with the fact that it does not clean or lubricate the engine. Parallel to that, it does not come in a concentrated state: 1 oz treats of product only 2.5 gallons of fuel. And there are complaints about the fact that its formula is a trade secret. As usual, this fuel stabilizer is only appropriate for gasoline engines: the company offers a different one for diesel and marine units.


Comes from 60 years of experience in the market
Impressive performance on several types of tests
Recommended by multiple car manufacturers


Does not clean or lubricate the engine system
Low concentration means high product usage
Proprietary formula with unknown ingredients

Best for Older Cars: Lucas Oil Fuel Treatment

Lucas Oil fuel stabilizer

Lucas is another stalwart in the market of petrochemical additives. This manufacturer offers a wide variety of products in that segment, so a fuel stabilizer is definitely not a surprise there. Just like the others, it will work on both two and four-stroke engines and prevents corrosion. In fact, the manufacturer states it can clean and lubricate the entire fuel system of your vehicle, including the fuel pump, valves, and injectors.

As you can see, there is little variation from one product to the other in this segment. This is another top brand in the market, so the main drawback we can mention is the high cost. Besides the fact that the fuel stabilizer’s bottle is expensive, you will have to apply 1 oz per gallon of gasoline. In other words, you will need a higher quantity compared to all the others. And, as usual, this product does not work with diesel.


Cleans and lubricates the car’s entire fuel system
Traditional manufacturer in this market segment
Works well on engines of many types of vehicles


High price compared to the other fuel stabilizers
Limited availability through online purchase
Low concentration means higher product usage

Iso-Heet Water Remover

Iso-Heet Water Remover

The name of this product says a lot. It is not a typical fuel stabilizer, but it does perform the core function of preventing water build-up. Besides that, it will also clean the injectors and prevent the formation of ice. The low price makes it an interesting option especially during winter, because it also makes cold starts a little easier. However, it does not have the best properties to protect your car’s engine for a long time.

STP Ultra 5-in-1

STP Ultra 5-in-1

Yet another traditional name in this segment; STP even sponsors stock cars. Now, this product is not a fuel stabilizer per se. It will clean the internal piping especially of modern engines, whose complex mechanics tend to deposit residual material more quickly. One bottle treats up to 35 gallons of fuel and is especially helpful to boost the lubricant’s performance. But this is not the best option for long-term fuel storage.

Royal Purple 11722

Royal Purple 11722

Among the many products offered by Royal Purple, this one aims to clean buildup and deposits from the engine. It is such an efficient product that the manufacturer states it can reduce the emission of pollutants by up to 18% as well as increase its horsepower. While that sounds a like too much, the fact that it works on any fuel seems a more practical advantage. However, it is also not the best for long-term fuel storage.

What is the best fuel stabilizer?

Our recommendation is the Star Tron Enzyme by a narrow margin. Both that and Sta-Bil’s product feature all the necessary qualities for a good fuel stabilizer. They are effective for a long time, treat many engines, and come from trusted companies. The top difference in favor of the Star Tron is its higher concentration because it makes it more affordable. However, you will be very well served choosing either one of them.

This time, our honorable mention goes to the STP Ultra 5-in-1. It is more of an engine cleaner than a fuel stabilizer, but it does that job brilliantly. Your engine will be protected against typical residual deposit and you will be relying on yet another traditional manufacturer. While STP also offers a typical stabilizer, your car will perform better than ever with this product especially if you are not planning to be away for long.

About the Author

Joe Stewart is a 35-year-old automotive enthusiast born in Miami, Florida. He is a part-time collaborator in AutomoBible and specializes at making car passion accessible to readers thanks to his product curations of all types.

Stewart worked in the automotive industry for several years especially in the field of accessories. He executed projects for several automakers whether to improve existing solutions or to design new ones according to their needs.

Nowadays, Stewart is expressing his passion for cars on AutomoBible. He is always looking for exciting new products and he tests them whenever he can, whether on his own 2020 Dodge Charger or on his friends's cars.