The myth of condensation in fuel tanks

[Renthorin]

I am under the impression it is not nearly as large of a concern as people say.

Here is an interesting read:

The Myth of Condensation in Fuel Tanks by David Pascoe: Boat Maintenance, Repairs and Troubleshooting

It pertains to boats I guess but wouldn't the same pertain to car fuel tanks?

I never top my tank off in the winter because I don't want that much gas potentially going bad and having to be pumped out of the tank in the spring.

Then again, is that just another myth? Does gas really go bad in 4-5 months of storage?

Inquiring minds want to know...and I do to

 

[Lee_Burough]

A critic of the writing in your link....

Deleted this post, to repost with correct spelling of "critique"

 

[Lee_Burough]

A critique of the writing in your link....

He sounds logical. But, he's outsmarted himself because the issue of humidity/moisture/water in a fuel tank is broader than the issue of where it originates. :smile:

Let me begin by saying that I don't really care where the moisture inside a fuel tank originates -His fixation on this point, and his assertion that it does not matter, are the fatal flaws in his argument(s). The metal surfaces with long term exposure to moisture will rust regardless of the source of moisture and available oxygen. Whether that moisture originates from the fuel, or the air inside a fuel tank is irrelevant to the health of a clean fuel system.

A full fuel tank doesn't contain enough oxygen to oxidize (rust) the inside of the tank....That, for me, is reason enough to keep the tank full.

If you are worried about stale fuel in Spring time, pump it out and use it in your other vehicles -adapter kits are available to pump the fuel out via the fuel rail.​

I bought a motorcycle with a nice frame, chrome, paint etc, but, to my chagrin, the inside of the gas tank was full of rust....Its worth it to keep available oxygen out of the tank by keeping it full of fuel.

The observation of rust on the inside of the valve covers is a red herring in his thought process. The cause of that rust, he concludes, is the moisture in the crank case and EGR system....Welp, a long, cruise prior to storage will eliminate 99.9% of that moisture....An oil change will be even better My fuel does not go through that environment, it won't contaminate my fuel -that is the overarching issue here- so I'm not worried about it! Let me say again, if there is no air space in a Fuel tank, the inside metal surfaces are not going to develop oxidation, because oxidation (rust) requires available oxygen....Doh!

How does he explain the condensation on your coke/beer glass during a football game? The laws of physics are not suspended because he's talking about reduced moisture available in a boat's fuel tank....His advice has missed the big picture and should be rejected....Oxidation, not moisture, is the process we want to control inside a metal tank, especially, during storage!

 

[Lee_Burough]

Moisture as a fuel....

The fuels industry recognizes that moisture will settle to the bottom of the tank in a few hours (The Air Force taught me it would be at the bottom of the fuel tank in about 45 minutes after refueling). The entire aviation industry operates on the conclusion that condensation in their tanks is a bad thing.

I think a full fuel tank will have less condensation than a half-full tank left in transient temperatures. Moisture as a fuel, is a whole other important question. Under boost, you don't want any moisture in your system.

At WOT, you may not have any room for error: A teaspoon of water at the wrong time could cost you your engine....Not worth the risk....

 

[salvageV6]

The Myth of gas going bad over the winter in your tank is far greater than the myth of condensation and rust in a partially full tank.

Just my .02.

Fill 'er up. :smile:

 

[Welby]

If I remember correctly, the inside of my Limited's tank is plastic anyways, so no rust. And as far as a teaspoon of water blowing your engine? Come on now...

 

[Lee_Burough]

If I remember correctly, the inside of my Limited's tank is plastic anyways, so no rust. And as far as a teaspoon of water blowing your engine? Come on now...

OK, I should have said blown head gasket : The idea of being WOT and on the edge, a teaspoon of water could cause the rear cylinders to be way lean and blow the head gasket. You were right to call me on it

 

[fitz3820]

I fill 'er up, add Sta-Bil for insurance and drive without the wastgate actuator hooked up until I burn all the old fuel.

Or I pump it out and put it in my wife's car

 

[zeus87gn]

I got all of ya beat.
We drive ours all year.
It doesn't get cold enough in south Ga to snow.
No worries! :biggrin:

 

[BASS]

Uh oh, im in the middle of resurrecting my car after sitting for 5 years. I kept only 5 gallons of gas in the tank over the entire 5 year period! I recently had all the old gas pumped out, but was wondering if the inside of my tank is all rusted out??

 

[Turbo6Smackdown]

first off.. bass.. yes, your gas tank is rusted. I'm sorry man.

Secondly, (renthorin) even if i didnt really KNOW for sure, if that was myth or fact, i still think that 32 dollars worth of gas, is still a low price to pay for insurance. changing gastanks sucks man. I'd do it lol. And does gas go bad? Well, I stored my honey in my buddies non heated garage, and probably started her up 3 times all of last winter and my gas didnt go bad so, I would say no. But, 5 years? Yea, i wouldnt drive that gas.
Just throw a bottle of stabil in it, and fill it up ALLL THE WAY to the top, and youll be fine. If youre kinda worried, get one of those better quality electric pumps, that has an inline filter on it, and pump it into one of your normally aspirated daily drivers, when winters over, and youre squared away

 

[8AV8]

bass... my car sat up 7 years. I took the tank out and filled it about halfway with water and with a friends help shook the heck out of it and emptied it SEVERAL times. When we got out all the crud we could with water we moved on to denatured alcohol. After SEVERAL times with denatured alcohol it was clean. Of course you have to clean the rest of the fuel system accordingly. This was 2 years ago and no problems.

ps-I had problems with fuel pressure and my return line was clogged also

chris

 

[Renthorin]

chris, just out of curiosity...how did you clean the return line?

 

[8AV8]

carb cleaner and air. I let the carb cleaner sit and work for 10-15 minutes and then hit it with air, the fitting on the air hose that you knock dust off of stuff with that has a tapered end. It fits OK in the return line. After several times back and forth I could hear bubbles in the tank. I kept doing it until I could hold a small tube to the return line and blow bubbles in the tank with my mouth. I killed two FP regs finding the problem though.

 

[VadersV6]

Fuel does lose a large percentage of its available energy after sitting for several months..at least thats what I heard from a guy who heard from his mother in law who heard from her history teacher who heard from his football coach who heard on short wave radio....

 

[Nick Micale]

Talked with some industry "experts" that stated shelf life of pump gas is about 3 weeks. it starts to loose octane after that period of time. Race gas in a sealed container, that is not translucent, can last a year or more.

A car sitting here in the desert heat for 4-6 months not only goes bad, but can leave deposits that will clog injectors, carbs, fuel pumps and even lines. This is not opinion, but from experience.

If you store your car for months, use a gasoline stabilizer or race gas, and keep the tank as full as possible.

 

[bison]

I bought a southern car early this year that hadnt run in 6 mos or so. When i dropped the tank to inspect pumps, i found inside of the tank completely rusted. There was no other rust on the car at all. Ive never seen one so bad. The fuel looked like someone crapped in t and stirred the hell out of it till there were no more chunks. Apparently it was rusted for a long time too. The filter was full of rust. I had to replace the tank and flush out the lines with fresh fuel before starting. The bearing in the engine were hammered. Probably form the lean outs and contaminated fuel it last ran with. Once these things start to rust they get bad really fast. he inside of the tank doesnt appear to be galvinized. I dont think a few mos. will hurt the tank if it sits, but years time sitting with only a few gallons in it will cause it to rust. If its full it wont rust. The only part of mine that wasnt rusty was the bottom which was covered by fuel.

 

[Turbo6Smackdown]

i dont know why people are using ANY denatured alcohol, or brake or carb cleaner, to try and clean a rusted part. alcohols chemical makeup doesnt cut a coating of rust on ferrous metals. Something like pb blaster, and a steel wire brush maybe. I know i know, you got examples of how it helped some of you in the past. but that doesnt make it right. wrong solvent. use a dedicated rust remover, and brush thats really stiff.

 

[salvageV6]

Here's what Chevron says about storage.

" 22. How long can I store gasoline without it going bad?

Gasoline stored in a tightly closed container in a cool place will stay good for at least one year. It is better if the container or fuel tank is almost (95 percent) full. If the container or fuel tank will be in the direct sun or will be heated above 30°C (80°F) much of the time, add an aftermarket fuel stabilizer to the gasoline when you first buy it. Gasoline-oil blends for two-stroke cycle engines stored under the proper conditions will keep as well as gasoline itself. "

One would think a dark TR gas tank in the winter could meet these requirements, especially if you plugged the vapor line.

All you need to do is watch the KR detector a bit when burning the tank off after storage.

I was gonna say it ain't rocket science, but I guess it is.

 

[8AV8]

The inside of my tank isn't ferrous metal...its plastic. How did you get a stiff wire brush on the backside of the baffles in your gas tank? Have you ever looked in there?

I used carb cleaner on the fuel return line...no stiff wire brushes are going in there. When I was actually doing this (not in theory) right or wrong was determined by if it worked or not. It worked...for two years with no problems:biggrin:

chris