Sta-bil Vs Seafoam - Which Is The Best Fuel Stabilizer? (2024)

Updated on May 23, 2022

Fuel stabilizers have been around since the fuel itself was created. They’re a necessary part of keeping the gasoline stable and are applied during the refinement process.

However, the shelf life of station-bought gasoline is just three to six months. Lawnmowers, boat engines, motorcycles, convertibles, and classic cars are often stored for much longer than that and need additional fuel stabilizers to avoid damage.

That’s where Sta-bil and Seafoamcome into play. Both products are designed primarily as fuel stabilizers, but also double as engine cleaners. The second functionality restores power to the engine, which is often misunderstood as a power boost.

In this review, we’ll compare the classic Seafoam to Sta-bil Storage and Sta-bil 360 Protection to see which one comes out on top!

Sta-bil vs Seafoam – Complete Comparison

To make the best comparison you can find, I’ll include more than just what the manufacturers write on the label.

The important factors in choosing between Sta-bil and seafoam are also application, effective duration, the effective cost of use, and the additional properties which may or may not improve performance and clean the engine.

Effective Duration

The first point of comparison is how long each of the products can stabilize the fuel. Even though station gasoline is stabilized for 3 to 6 months, in real-life conditions the protection does not last that long.

Many boat engine and lawnmower owners have faced issues with leaking carburetors and corrosion after leaving the fuel inside the tank over the winter.

1. The Sta-bil Storage fuel stabilizer provides up to 24 months of protection, depending on the concentration.
2. The Seafoam fuel stabilizer provides up to 24 months of protection, depending on the concentration.
3. The Sta-bil 360 Protection fuel stabilizer provides up to 12 months of protection.

The Sta-bil 360 Protection offers only 1 year of protection, so if you plan on storing the fuel for longer than that, the Sta-bil Storage of Seafoam are your two choices.

The Winners: Sta-bil Storage & Seafoam

Stabilizer-Fuel Ratio

This point is going to be the most important, as the amount of fuel stabilizer used directly affects the quantity and price of the stabilizer.

The following ratios are based on the 12-month storage period:

1. The Sta-bil 360 Protection – 1 ounce per 5 gallons of fuel.
2. The Sta-bil Storage – 1 ounce per 2.5 gallons of fuel.
3. The Seafoam – 1 ounce per 1 gallon of fuel.

The difference here is more than evident – Sta-bil 360 Protection is twice as effective as Sta-bil Storage, and 5 times five times more effective than Seafoam. For a 24-month storage period, the amount of Sta-bil Storage or Seafoam should be doubled, but Seafoam recommends going even beyond 2 ounces per 1 gallon of fuel.

The Winner: Sta-bil 360 Protection

Price Per Gallon of Fuel

To get the real cost of using any of the three fuel stabilizers, we have to look at more than just the base price. Because Sta-bil Protection does not come in a 16-ounce container, we’ll compare the 32-ounce Sta-bil containers with the 2 x 16-ounce cans of Seafoam deal.

Image	Title	Price	Buy
	Sea Foam SF-16-2PK Motor Treatment Multi-Use, 16 Ounce, Pack of 2		Buy Now
	STA-BIL 360 Protection Ethanol Treatment & Fuel Stabilizer, 32oz		Buy Now
	STA-BIL Storage Fuel Stabilizer, 32oz		Buy Now

It’s clear from the table shown above that things do not bode well for Seafoam even before we get to the price per gallon of fuel. Based on the current prices, Sea Foam is a few dollars more expensive than Sta-bil 360 Protection, and double the cost of Sta-bil storage.

Sta-bil is the better fuel stabilizer based on the price and price-per-gallon metric. Initially, I wanted to use the price per single gallon of fuel, but after doing the math I realized that the costs of using Sta-bil would be so trivial, I increase the volume by 10.

The decision between Sta-Bil 360 Protection and Sta-bil Storage depends entirely on whether or not you need more than 12 months of protection. The marginal difference in price would make Sta-bil Storage better overall, but Sta-bil 360 Protection is the newer product so I’m leaning more towards it.

The Winners: Sta-bil 360 Protection & Sta-bil Storage

Added Fuel Additive Benefits

We’re all aware that modern Seafoam is more than just a fuel stabilizer, but what about Sta-bil? Both brands will legitimately clean the fuel system, fuel injectors, cylinder walls, piston heads, and valve heads.

There is a ton of video evidence online, and you can test it yourself – all you need is a boroscope. Add either stabilizer to a full tank of gas and make sure to make the mixture rich, and once you’ve run through the gas, pull out a spark plug and insert the camera.

You’ll see how clean the engine gets, and if you’d like to see the before-and-after images, use the boroscope to inspect the engine before you start running fuel stabilizers.

The features presented in the table have been taken from the official websites for Seafoam and Sta-bil, and give us more of an idea of what the marketing strategy is, rather than the actual results. Don’t get me wrong, all three products meet their promises, but in real use the difference in effectiveness and targeted parts is minimal.

The Winner: Seafoam

FAQs

What is the shelf life of fuel?

Fuel cannot last forever – in a closed container like the fuel tank or a jerry can, gasoline can last between 3 and 6 months, while diesel can last for a year. The organic-based ethanol has the shortest lifespan, just a couple of months is enough for oxidation and evaporation to render it unusable.

How to identify bad fuel?

The chemical properties of gasoline change over time, causing discoloration and a darker brown color. If the fuel gets a red hue, it means there’s some rust on the inside of the container or the fuel tank.

Most of the time, visual inspection is enough to tell whether the fuel has gone bad. The smell is another clue, as fresh gasoline has an extremely potent smell, while bad gasoline has evaporated to the point where it barely smells like anything.

Modern vehicles will also report a problem with fuel in case it’s gone bad. In older vehicles, you’ll experience a severe loss of power, hard start, and stalling as the fuel lacks the volatility to make powerful combustions.

Is Sea Foam better than Stabil?

Both Sea Foam and Stabil Storage can keep fuel in good condition for up to 24 months. However, Stabil Storage costs half as much as Seafoam and is 2.5 times more potent, so it provides a much better deal overall. In this review we’ve covered the costs of running Sta-bil and Seafoam, so make sure to check it out!

Can I use Sea Foam and Stabil together?

Some people mix the two products, but honestly, I’m not sure what the effects would be if you combined them. I’m fairly confident that nothing bad would happen, but it’d still run them separately and alternate between them.

Is Sea Foam considered a fuel stabilizer?

Seafoam is first and foremost a fuel stabilizer, with the added improvements helping to clean and maintain the engine. If you need to store fuel in the gas tank or a can, use Seafoam to keep it fresh for up to 2 years.

Which fuel stabilizer is the best?

Based on the factors presented in the comparison, Sta-bil 360 Protection is the best fuel stabilizer currently available on the market.

Can you put too much Sta-bil in your gas tank?

You shouldn’t go overboard with Sta-bil, but you can safely add 2 or 3 times the normal amount to the fuel without any detriments to the engine or the fuel itself.

Will Sea Foam harm your engine?

We’ve covered the topic extensively in our article on the truth about seafoam, but in short, this fuel stabilizer and additive cannot harm the engine and can affect it positively by cleaning the residue build-ups.

Verdict

We’ve looked at what the Sta-bil and Seafoam fuel stabilizers have to offer, and it’s clear that the Sta-bil 360 Protectionis the clear winner.

It offers the best value for money, provides up to 12 months of protection, and all the benefits of cleaning the engine. If you need to keep the fuel stored for longer, get the Sta-bil Storage, as it offers similar benefits to the 360 Protection at a much more affordable rate than Seafoam.

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