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Hagerty Employee

Is your fuel stabilizer actually hurting your car?

Putting your beloved ride away for the season and enduring months of watching it sit in place, wishing you could just go for a drive, is an unfortunate reality of winter vehicle storage. Worse is the notion that your careful storage prep routine includes a common misstep that will set you up for a bad experience come springtime. That’s exactly what FortNine digs into with this latest video about fuel stabilizers ... 


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You get what you pay for. Stabil is a good proven product. 

Ethanol is just a fact of life in most areas and you need to deal with it. Stabil and filling the tank full is key.

On 2 cycle engines it is Recommended to use Stabil in ever can of mixed fuel to keep from damaging the engine with ethanol fuel. 

I just pulled a tank that was mostly empty and could see the damage in the tank. The sender was rusted up and we had to replace the tank. 

Use Stabil, fill the tank with premium fuel and drive it once good weather arrives. Sitting even in the best conditions kills cars. 

Intermediate Driver

You might also want to use a product called "STAR TRON". This eats up the ethanol in your gas.

New Driver

A word of caution about using premium fuel.  We hopefully all understand which cars can take advantage and/or need premium for the spark knock problem, but a secondary issue comes into play. Beware of getting premium when you are in a less-popular gas station out in the sticks. It has a greater chance of being older and with more water in it than from a popular station. If it does bite you some gas treatment can help absorb the water. That's the only time I would use gas treatment, not sure of it otherwise.

New Driver

What are your thoughts using Sea Foam?

Pit Crew

I've always used non-ethanol "recreation gas" in my old cars - here in Michigan it is most easily found at Speedway stations, and is 89 octane.  This works well in my 1955 Ford Crown Vic, 1968 MGB/GT, and 1967 Austin Healey 3000 MKIII 3000 - all with stock engines.  For winter, I also add Sta-Bil, before a long last drive of the year.  This has always seemed to work well - the cars are stored for 4 to 6 months.  I hope everyone can still get out for that "last drive" before they have to tuck their "babies" away for the winter!

Intermediate Driver

I'm in the camp of leaving tanks empty. For any engine I plan on storing, be it a lawn mower, generator or car engine, I empty the tank and run the engine until it dies a natural death. Totally devoid of fuel. While some may think this is sacrilege, my thoughts are the less ethanol, the better. Once the remaining fuel evaporates, nothing is left but an inert engine. I store my toys in climate controlled rooms and garages so there's less of a chance of condensation from temperature changes. 

Intermediate Driver

In the province of Ontario, the only ethanol-free gas available is Shell Gold V-Power.  As such, I use it exclusively in my collector car (and my lawnmower!).  I pair it with a full tank of fuel and Sta-bil in the fall and I've never had an issue in the spring.  

Pit Crew

I’ve used sta-bil for years in my stored mustangs, glad to know it’s still a top choice. Topping the tank, and using premium or the lowest ethanol containing gasoline, has kept moisture to a minimum for my vehicles. Starting the vehicles regularly, keeping rodents and insects at bay are my primary concern.


One of the best places to find non-ethanol gas are farmer cooperatives.  Which sounds ironic since farmers grow the crops that are processed for ethanol.  One of the local co-ops has non-ethanol in 87, 89 and 93 octane.

Intermediate Driver

Maybe that's because farmers know equipment and avoid ethanol themselves.


I have never used Sta-Bil in my cars, I have however been known to take them out and drive them a few times during their "storage period" and get some fresh gas. Normally I hit the road a couple of times a month over the winter, although I have been known to let a car sit from mid January to March. I have tried Sta-Bil in my lawn and garden equipment and come time to use that equipment and I was not happy as it was way harder to start than I would have liked. In the end I just start and use stuff. When I shut off the tractor and generator I shut off the fuel and starve them so there is nothing or very little in the carburetor. I know this is the wrong thing to do but it has served me well for over 10 years. The Snow blower doesn't have a shutoff valve so it gets to come out on Summer days and run for a little while on the lawn while I am mowing. My 1971 Snow blower gets three roll over pulls before I prime, choke, and switch it on and then it starts on the first pull, last major service was in 2009 other than that it is just yearly oil changes. I will continue to do what works for me, thanks.

New Driver

I used Stabil religiously in all of my cars until I noticed a buildup of a crusty red substance on the Carburetor of one of them. I live in So Cal so my cars don't ever sit more than a month. I am one to keep the fuel low and ad fresh fuel with Marvel Mystery Oil added every time I drive the cars. I only found the red gooey stuff on one of 15 cars. Maybe too much Stabil in that one???????

New Driver

I had a dirt track car powered by a Yamaha R1. I used Stabil over one winter, and in the spring, it would just not fire though it was always an easy starter. It took some time, including a new wire harness, before I found the real problem was the fuel injection nozzles were clogged. After that, race gas only. And now, in my Porsche and BMW that sit over the winter, there is only ethanol-free all the time.

Pit Crew

Luckily, my station has ethanol-free gas and that is what I have run since the first tankfull.  I continue to store my car in winter and add Sta-bil to the tank.

Intermediate Driver

Glad to know Stabil works, as I've been using it for years, on my Harley Davidsons, my boat and my Corvettes. I guess I'll stick with it, since it works, and I always store my vehicles with full fuel tanks. Don't have much choice in this part of the country to find non-ethanol fuels, unless I use "Trick" fuel, which comes in several flavors up to and including 114 octane.

Intermediate Driver

Never used any additive other than Race Gas Concentrate.  

Pit Crew

For those that aren't aware of the site, you can go to to find sources of real gasoline in your area.


Marinas are usually a great source.

Intermediate Driver

Having worked on boats for years there were times when the red Stabil would make a needle valve stick in a carburetor. And when stored to long the fuel was junk anyway. We did have better luck with the green Stabil that is supposed to deal with ethanol better. 


I've been using Sta-Bil for ever, and never had any issues in anything I had from boats to bikes, cars, and tools, and I never run them out of gas, as I was told storing them for long periods empty causes gaskets to dry. But one the Gas Companies went from the MTBF?? additive to Ethanol, I started using the Sta-Bil for marine use (the blue stuff) as it deals with moisture better than the regular red Sat-Bil. Actually, I add Sta-Bil year around on anything with an engine...


I've moved to SeaFoam, as it is made for marine applications.  I'm fortunate in that I store my cars in an area that sell premium gas with no ethanol added.  I run the tank as low as I can and then fill with the non-ethanol premium (93 octane) gas with SeaFoam.


Stabil has a marine formula that has more corrosion inhibitors.  I use it in my boat and car.

Pit Crew

Truth be told, there's little need for these fuel stabilizers any more.  I use one of those plug-in OBD monitors that connects via bluetooth to an app on my smart phone.  With that app, I can monitor many various engine parameters.  Because my 2015 Chevy Express van was designed to run on "flex fuel" (up to 85% ethanol), the computer automatically, quickly and continuously calculates the ethanol percentage in the fuel.  The result is that I almost never encounter any ethanol, even after filling up at pumps that state "contains 10% ethanol."  (Not just "may" contain.)  Even after filling up at those pumps, the ethanol percentage is still almost always "0."  Once in a while, I get a reading of "4%) or "6%" after filling up, which tells me I just got a tank of 10%, which added to the gas that remained in the tank, works out to about 6%.  


I don't know why this is.  Maybe with the elimination of government subsidies to the ethanol industry, refiners find it too expensive to dilute the gasoline with ethanol.  

Pit Crew

I buy ethanol free gas from a local gas station in my area for most of my vehicles and lawn equipment.  I still throw some "Star Tron" fuel stab. in the tank to be sure,  BTW, I always top off the gas tank before storage to keep moisture out of the tank, as recommended by my mechanic.  If the tank is full, there can be no moisture in the empty air space from the changing temperatures over the winter.  Seems to be logical to me.  And an extra bottle of Star Tron in the tank is my choice before long term storage.

Intermediate Driver

I can't begin to tell you how bogus Fort 9's amateurish "lab testing" is.  None of his tests take place in the sealed\environment of a modern gas tank, nor even the partially sealed environment of a pre evap emissions compliant tank.  Not to mention his lack of distinction between the ability of a hydrophilic additive to draw moisture from the fuel itself or the air surrounding it. 


This guy has never done a legitimate test of materials.  He shoots bb guns at helmets to "test" their impact resistance.   He also sets fire to them--a standard not even included in any MC helmet testing done in legitimate labs.  So who cares?


This guy's "work" is  joke.

Pit Crew

I do not use Stabil. I only use non ethanol premium fuel with Seafoam not only before storage, but all of the time. This has served me well in my 45 year old convertible. 

Intermediate Driver

Whew! I was freaking, glad I to have used Sta-bil for years. As for bikes, we have stored them with rec-fuel only for years, as we are not far from Roy's General store where they have it right at the pump. Excellent! Loved the Vid. Great job thanks, nice to know I have been doing one thing right!


Have used Stabil for years. Also always use only Ethanol free premium gas year round in my Corvettes and small engines.


Is "Dry Gas" or "STP Fuel Supplement" any better or worse to control water buildup in the gas tank?

Intermediate Driver

I am an outlier, as one of those guys who has maybe used Sta-bil a couple of times over the past 31 winters. I actually have a few bottles in my garage, but do not use it.  
As mentioned in the video the worst thing for E-10 Gasoline is H2O.  Ask yourself, how could you keep H2O out of the fuel system?   It is not something that will just magically appear out of nowhere; obviously moisture has to be introduced to the system.  Logically Fuel lines should not be quickly affected because ultimately if you have no H2O in the system to start with then you should not have it in the fuel lines to pull out the ethanol.   H2O should not move into the fuel lines until the car is started, and that is only if there is any H2O in the tank.  

Therefore the most likely culprit for moisture to be introduced to your fuel system is in the fuel tank itself.  The ONLY way for moisture to be introduced into the fuel tank is via the filler neck, a vent if your car has one, or some other hole.   How water enters the fuel in the tank is via the surface of the fuel as shown in the video, and the more surface area you have the more moisture can be introduced in a given amount of time. 

Filling your gas tank all the way may be the best thing you can do for storing your car over the winter, here is why...
1) It will reduce the surface area of the fuel in the tank.  Simply put, fuel tanks have rounded corners, they are not simple cubes.   This means when a fuel tank is full there is less surface area of fuel for moisture to be introduced
2) If you have a higher percentage of fuel, this means there is a lower percentage of air for moisture to accumulate. 
3) Finally, as discussed in the article and the video all of those additives which are in Gasoline are volatile, and they will eventually evaporate.  As an example, if you have a single gallon of fuel in your tank in the fall, by spring it will most certainly be gone, if you have 100 gallons (with the same surface area) it will obviously take longer for it to evaporate.  Remember that evaporation occurs at the surface, lower surface area means less evaporation of those volatile chemicals, more fuel means it will take longer for the volatile chemicals to evaporate and your concentration percentages will still remain reasonable.

Every fall, I fill my tank with Premium Fuel (Typically Exxon/Mobil, BP, Shell, Sunoco) as the very last thing I do before parking it for the season.  I have been doing this for the past 30 years, never had a problem, and I do not use any fuel stabilizers. 

Pit Crew

I still find it astonishing that ethanol mixes are still with us.  What exactly are the goals of it, apart from lining the pockets of the ethanol industry?  It's not cleaner (in fact it is worse for air quality), it doesn't do anything for the environment, it has caused millions in damage to existing engines and machinery and it creates worse fuel consumption across the entire vehicle fleet.  It also drives up food prices by taking out agricultural land.  The horrors of palm oil plantations in south east asia taking out rainforest habitat (more for biodiesel, but related).  It should be a niche product for boost fans (E85) and yet it's everywhere to the point people pass around non-ethanol pump locations like speakeasy tips.  I don't understand why biofuels are still with us after 10+ years of failure to produce any of the objectives they promised.

Community Manager

From what little I've read about, you got it right in the second sentence. The corn lobby is apparently a big one.

Intermediate Driver

I have for years only purchased Ethanol free gas for my 87 MCSS. I find the octane is a bit higher and even though the cost per gallon is higher after a few months gives me no problems. I can say that before I switched several years ago I had to replace the gas tank but am not sure I can place the responsibility on the Ethanol gas but seem like a likely choice.

Intermediate Driver

We live in the country, lots of dirt roads.  Our Model A stays in the shop but as long as roads are free of any salt slush we keep right on going, use the car whenever possible, never worry about gas, no matter what we're using.  It starts in 20 below no problem, manifold heater helps a lot.  An idle car is the devil's workshop ~


A friend of mine uses sea-foam for years and has not had a problem with it . Some one else said that sta-bill  has a limited shelf life ???

Pit Crew

I began using Stabil 35 years ago when I took my 1969 428 Mustang out for a late winter run and nearly burned it down due to all the fuel leaking from the float bowls onto the top of the engine.  The float bowl gaskets were shrunken and deteriorated due to the gas going bad over the winter.  Since then I have used Stabil in nearly everything (just not my daily drivers).  I worked for a very large auto OEM in the powertrain area and discussed Stabil with a respected fuel specialist. He said that the most important thing is that Stabil is an anti-oxidant and the oxidation is what causes fuel to break down.  He wished that the oil companies would blend it into all the fuels. Ethanol is another issue altogether.  You can look up a study by Mercury Marine on this topic.  The answer is to either drain the tanks OR fill them full so that there is little to no air space.  For me, it is generally difficult to drain tanks.  My answer for years has been to fill them.  Yes, you lose a little volatility over the winter, but it never seems to be a problem.  So, today I use Marine Grade Stabil in all my equipment-boats - carbed and fuel injected (up to 40 gallon tanks), lawn and yard equipment, 428 Mustang, emergency generator, etc. Marine grade has extra corrosion inhibitors to fight water. I leave gas in the generator for two years with a double dose, then if it isn't used, I'll drain it and burn it in another engine.  No problems ever from using the stabilizer. When I buy a can of fresh gas, the stabilizer goes in at the same time.  The ethanol will rot some fuel lines on small equipment, but that's not the fault of Stabil.


Intermediate Driver

Filling a tank with ethanol will not work.  It will still rust badly, very badly.  I do not burn ethanol in anything anymore and never will again.  It's garbage fuel that needs to go away.


If you can get it, 100/100LL AVGAS, it has many great additives and one that absorbs moisture.  I run it year round in all non catalytic engines such as motorcycles, quads, outboards & inboards, generators, chainsaws, weed whacker, my 1958 Corvette, my 1948 Aerosedan and airplanes.  Real gas, no ethanol, no moisture, no rust!  

Pit Crew

Here in Ontario Canada, After cleaning carburetors each spring and fall from the green stuff left behind I realized that it is indeed the ethanol in regular 87 ( up to 10 percent) I call BS on that, started to use only premium fuel. in everything.

Now I always add sea foam to anything that has to be stored, Boat motorcycles, lawnmowers weed eaters, chainsaws and on and on. never a problem. Thank you for the investigation as I can see it is the ethanol that is the issue here. I will continue to use Premium (97 Octane) and sea foam. as it has solved all my problems of the past.

Advanced Driver

unfortunately the study left out one independent variable: O2. Leaving assessed it's need in combustion, it is THE croder ( of all 'stuff'). The beakers I saw were all open topped in this vid. Our gas tanks R not (unless the 'cap' is left off). Only O2 available is in the gasoline (& 'un-topped off area). Some commenters have mentioned this - low O2 gasoline and full tanks can help. An 'oily' additive like stable & k 100 can take care of the rest.


I'd leave the plow truck idle for 6 mo in the past (pre-Y2K), come out & it would start (sometimes w/a lill battery jump) right up.  Now w/the 'new gas' - no way w/o stable (anda full tank)...


I agree with emptying the gas tank, particularly for 2cycle engines.  But it's not always easy to empty your vehicle's tank.  

Ethanol is insidious stuff.  It is extremely corrosive.  And it absorbs moisture (water) like a sponge.  So, the water settles in the bottom of your gas tank where the high-pressure fuel pump (that is required for the fuel injection on modern cars) is located.  After several years, particularly if you don’t drive your car every day, the water, combined with ethanol, rusts and corrodes the pump, rendering it inoperative.  Most of the time, replacing it requires dropping (removing) the gas tank to get to the high-pressure pump.  About half the time the bottom is in such bad shape that the whole tank will need to be cleaned or replaced.  I don’t drive my 2000 Silverado truck every day anymore; therefore, the water and ethanol don’t stay stirred up.  I recently had to have the pump replaced and the tank cleaned.  The tank’s condition wasn’t too bad, so I’m lucky; but it still cost me $500 for a new pump and labor.  

HEET® gas line antifreeze is a product that is advertised to prevent and treat freezing gasoline lines, but they say it will also remove some water.  I used it when I maintained a friend’s car collection several years ago.  It didn’t hurt anything but I honestly don’t know how much, if any, water it “removed”. 

Some folks tell me they don’t need to worry, that they don’t live in an area (mostly Dallas and Houston around here) that requires 10 – 15% ethanol in their gasoline.  Doesn’t matter.  The ethanol is so corrosive that the oil companies won’t allow it in their pipelines!  Therefore, it is blended in at the distribution centers.  So, a tanker truck that delivers blended gasoline from the Dallas area distribution center may also deliver to areas outside of the Dallas area.  If the driver still has ethanol blended fuel on board after he has delivered to all of the stations that require it, he will deliver it to areas that don’t require ethanol and you get a dose of it anyway.  

I refuse to take any chances with my 1985 boat.  It has a 350 Chevy I/O with a Holly carburetor, rubber fuel lines and fuel pump diaphragm that can’t tolerate ethanol.  So, I buy racing fuel.  Costs me $8-$10 per gallon.  But worth it.  

Dallas Texas

New Driver

What would the results be if the test bottles were covered and pretty much air tight like out gas tanks?
New Driver

What about Stabil 360?

New Driver

what about Stabil 360? would tests be the same if test bottles were covered or air tight. More similar to our gas tanks?
Pit Crew

All my seasonal vehicles and equipment are stored with FULL tanks of non-ethanol, premium gasoline AND SeaFoam as a stabilizer/system cleaner as insurance. Full to prevent condensation in the tank. Empty or non-full tanks are invitation to moisture, and will especially damage steel tanks and fuel systems with interior rust.

I thoroughly believe this to be the best practice, I’ve done this for decades now, and have never had ANY fuel related issues since my first negative experience with ethanol based fuel that started me on this practice.

I had a 1980 motorcycle that I stored with a full tank of fuel as I always had, BUT this was one of the first years ethanol was being added to “water down” gasoline. At that time, we did not know what we know now about the problems ethanol gasoline can cause. The bike actually sat in storage for 3 years this round, because I simply had no desire to use it. Then one summer, I had the “bug” to ride and I took it out. Put the battery in and turned it over, it wouldn’t fire. I popped the gas cap, the tank was empty. I was sure I stored it full but maybe...? So I proceeded to pour new gas in the tank and I had a “shower head” of holes raining below! The still sitting ethanol separated to the bottom of the tank and rotted it through. I bought a new tank, new gas, still no fire. I found the carburetor totally gummed up with a green algae over a thick layer of yellowish “paste” below. After a thorough cleaning, the bike ran well again. Ever since, I’ve practiced this new storage method, and the inside of my steel motorcycle tank is still like brand new. Clear to the bottom. At one point this bike sat in storage for several years again, then when I turned it over, it fired right off. 


Spring storage: 1 Fill tank- 2 add 4oz of Marvel Mystery Oil per 10 gals of gas-3 Start and run engine every week-10days to keep the carb full of gas. This will save fuel hoses and carb gaskets and seal rings from dry rot and prevent tank moisture. Back when we were blessed with real gasoline, tetraethyl + lead accomplished the same preventive measures right from the pump, tetraethyl being alcohol. 

Pit Crew

I believe I have to rate this YouTube as the best one I have ever watched!

Intermediate Driver

Living in a Moderate winter zone, Pennsylvania, I drive my car. As long as the roads are clear of snow and road sprays/salts, I will take her out for a nice winter drive when I can. Cars are meant to be driven, not stored. Of course I know in many other areas you have to store your classic because there is just to much snow.


It's not the snow that keeps my old cars under cover, it's the crappy salt mix that they spread on every street here in the midwest.

I used Sta-Bil in my recently bought Model A and left the tank low, thinking I'd install the new fuel gauge, sediment bowl, and redo the fuel lines. I didn't touch it.

The engine is a 260 Falcon V-8 and electric fuel pump with Michigan gas in it.

Here in Illinois they make that corn fuel additive.

New Driver

I run 100 Low Lead aviation fuel in my rod, & I don’t have any fuel storage issues...

yes, it’s a little more expensive & you can’t use it with anything that has a catalytic converter,

but the carb & fuel lines stay clean & doesn’t attack rubber lines or gaskets..