I've heard that you should fill the gas tank when storing a car for the winter to avoid condensation. If the car is stored in a fully heated garage, is that still necessary?

 

I'd leave a little room for thermal expansion. Liquids are incompressible!

 

I’ve stored boats in my garage during winter hibernation and never stored them with full tanks.
If the car sits all winter, the gas will probably all go bad by spring.
Would you rather deal with a gallon or two of bad gas or 18 gallons of bad gas in your tank?
With todays gas, make sure you add some race fuel, Staybul or other additive into the tank and run it through the carb or efi before you put it in storage.
Full or empty I always shake the back end of my car or boats, just enough to get the gas in the tanks to wash up onto the sides of the tank to coat them again and again.

 

Right on. I am lucky enough to have access to Non-Ethanol gas here in upsate NY, so I always use it.

 

Full tank with stabil and forget about it until spring. Been doing it that way for a very long time up here in the frozen tundra.

 

Gas will be fine until spring.

 

I run non-ox premium in my hot rods and all small engine stuff. I pull the batteries out of the boat and lawn mower and store in my heated work shop. Our 20 Mustang is stored in my cold storage shed. I don't pull the battery. Just trickle charge it once a month.
Using non-ox premium I've never had a problem.

 

I used to "top-it-off" for storage. If you have ever had a fuel line, carb, fuel pump, or gas filter leak, I would rather handle $10 worth of gas on the floor than $70 worth.

The less gas in the tank now, the sooner you can get some fresh stuff in there in the spring.

Best answer: post 3. I would like to add that if you do treat the tank, run the engine several minutes to get the additive all the way into the carb.

 

i use a battery tender and usually have a half tank in it and i start mine during winter at least once and let run till it get to temp.

 

So so so many ways that have been successful for many different folks. I’ve tried many myself. I’ve never had any issues with trying any of them. This off season,, I’m filling up with ethanol free 90 octane and forget about it.
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should be fine,, ,, right..?.??

 

On Private aircraft they taught us to always leave the airplane with the Fuel tanks full of gasoline. I would normally fly my Cessna on Automotive gasoline ( I have the STC for this) and for the winter months I would use the 100LL aviation gas they sell at our airport. On my Corvettes I fill them up with a ethanol conditioner and then fill the tank with pump gas. It is the ethanol that likes to do the damage in our engines then a bottle of conditioner should provide sufficient protection.

If there is space above the gasoline for air in your Fuel Tank then it has space to create condensation (water) inside the fuel tank. No space means no room for water. I saw this recently when we had almost a pint of water inside the newly installed fuel tank after some wacky weather. Had the tank been full of gasoline there would have been less water. In a temperature controlled garage you should be okay but I would still keep it full of gasoline.

Batteries are another matter all together, you will need a rubber apron, rubber gloves and eye protection to really be safe "working on a automotive battery". They need to be kept at a "Full State of Charge (SoC) during the winter months to avoid loosing capacity. Many cars never fully charge a battery with their alternator. I remove the batteries and put them in a heated garage hooked up to a battery charger. The physical body of the battery is cleaned before taking it into the garage. I also check the electrolyte levels by removing the caps on the battery's top. Any leakage of electrolyte on top of the battery near the posts should be neutralized and removed before charging. If the electrolyte level goes low then the lead plates surface get exposed to the air will start to oxidize. It is important to have a gallon of Distilled Water around to use in topping off any used electrolyte. You need to be sure that the battery case is not dripping or leaking any electrolyte out before handling it around your car. The charger is set to charge at ~15 amps (@12 Volts) and comes on with a Timer. The timer ensures that the batteries are fully charged at least once a week. Before batteries are returned to service they are charged above 2.5 Volts per Cell which will make them gas and circulate the electrolyte keeping it from stratifying.

In year past I tried to use a Battery Tender device and I installed it in mid-November and by early mid-March all of the electrolyte was boiled away and you could see that the cell floor was dry. There goes another $150 for a new battery. The tender I used was rated for 750 Milli- amps of charging current and it did not regulate. So the lesson here is be sure that your Battery Tender has the built in ability to regulate the charge flow. The BEST thing for your battery is to start your Corvette and DRIVE it for 20-30 minutes.

Battery maintenance is critical to a long serving/lasting battery. The problem is that your C3 was designed for a Flooded Lead Acid (FLA) battery and not one of the newer Absorbed Glass Mat, Lithium Fe or Spiral batteries. Keeping it at or near Fully charged will ensure it will serve you for a while. Batteries left partially full will start loosing capacity in most cases, permanently. The Absorbed Glass Mat batteries can go for a lot longer as they have a very low Self Discharge rate when compared to that of the standard FLA Battery. The older a FLA battery is, the faster it will Self-Discharge. Keeping the electrolyte levels full will ensure that your capacity will be there in the spring.

Keep your Fuel Tank FULL and your Battery FULLY Charged to assist in a quick getting the car ready in the spring!

 

And if you do get a little water in the fuel tank:https://www.goldeagle.com/product/he...water-remover/



Works great! Stuffs been around forever. I remember my dad using it in the 60's.

 

OK so when we say 'full', I just filled it to the point of it looking like there was about 1 inch to the filler neck. The fuel gage is peaked above full. The response from @ignatz above was to leave a little room. Does what I did sound correct or should the gas be all the way to the filler neck base?

As far as the battery, I have a kill switch on it, the car is in a heated garage below the house, and I fire it up for 20 minutes once a month through the winter. That should suffice, right?

Short of buying a car sized treadmill or putting snow tires on it, that's about all I can do.

 

Kinda like this.
I too have a heated garage. The temp never gets below 45*. I normally park it, with pure gas in the tank, for it's winter hibernation somewhere around the end of November, beginning of December, depending on the weather. Fuel gauge needle is just a tick past the 3/4 mark with a battery maintainer plugged in. The next time I fire up the engine is usually end of March, beginning of April, again depending on the weather. Never had any problems. Starts and runs just fine.

 

There was a C1 & C2 discussion a few months back about gasoline longevity with a link to an article. The recommendation is to use premium for longer storage life. Regular degrades in ~3 months while premium lasts ~9 months before degrading.

Here is a paragraph in the article from a Sunoco Tech Specialist:

 

Routine for over 20 years, car has 120K+ miles. Fill up with 89 octane, drive to the unheated storage facility in mid November, park it, in neutral & emer brake off. Remove neg battery cable and put a car cover on it. April 1st to the storage, cover off, neg cable reinstalled, starts right up ,and drive home & continue to use the gas until it is time to fill. Never a problem, no bad gas indication.

 

My routine with the Vette starting with the winter of '76-'77..

I have never used ethanol since it's inception, never filled the tank, never used a stabilizer, never had a problem..