How to keep an empty, clean gas tank from rusting?

Hi all: We've had topics on cleaning out tanks, and they've been helpful. Now, what does one do after?.

My nephew's truck has dual tanks, and he's been running offf of one tank; this weekend we're dropping the other tank, cleaning it out--the removed sender was highly gunked up--and reinstalling.

He has no need to carry around 40 gallons of gas until next January when he drives cross country. So in the mean time, once the tank is cleaned and reinstalled, to prevent it from internally rusting I was thinking of "fogging"" the tank with fogging fluid, or, put a couple of gallons with double the normal about of Stabil--as they reccommend for long fuel preservantion.. ( I have not used used Seafoam, and I understand that's more for cleaning than preserving fuel.)

So, what's say, group.? Thanks, Bob

The easiest way is to fill it with fuel, the other way is probably to line it with something. You can buy tank liner for motorcycles - actually one of my bikes has the tank lined with something that's designed to liner aircraft tanks - but that might be both an expensive option and one that's not easily applied to a truck tank (fancy sloshing some chemicals around the tank by turning it around every few minutes to ensure the lining gets into every nook and cranny before it sets?).

In essence you want to ensure that you don't get any moist air in contact with the bare metal of the tank. Hence, I'd just alternate between the tanks.

+1 The best advice is to run both tanks in order to keep everything operating OK. What's the downside? Obviously the cost of a fill up is high when using both tanks, but the frequency between fill-ups will be longer as well.

I'd agree with the alternating tanks, but, he's in the Navy undergoing sub training, and he's not exactly flush with money. I said, just go with one tank, but that's not flying.

A little more info: 1978, Big block, 90% interior and exterior restored with gorgeous pearl white paint and low cowl induction hood, really nice wheels and tires. And it's getting a 5 speed manual in a couple of weeks. SOOO, he wants to keep it functional and looking good at the same time.

I've already offered to swap my two cars for his truck...

The fogging treatment should work. I don't think the Sta-bil will do anything to prevent rust. Since the tank is going to be out of the truck, I'd think you could just pour in a little bit of motor oil, slosh it around to coat all the walls, drain out the excess and then put the gas cap on.

Run it dry, fog it with WD40.

I still think alternating tanks is the right answer though. No carrying extra fuel, no filling up 2 tanks, no BS with fogging or rusting.

Quart of oil, drive over some speed bumps? Drain prior to use.

why not fill both tanks.. run one until it is empty, then switch to the other and refil the one you just emptied. Yes, you carrying around extra weight and fuel, but as long as you alternate tanks, you are only ever filling one tank at a time.

I don't think WD-40 has much, if any, rust-prevention additives.

I would use 2 cycle oil and gasoline mix in the tank. Mix a small ratio like 5:1 gas to oil. You would need no more then 1-2 gallons of fuel. When you do need to use the tank and add more fule, there will be no problems, not like some other solutions that have been suggested

chuckles wrote: I don't think WD-40 has much, if any, rust-prevention additives.

http://www.wd40.com/faqs/

I don't think its the ideal choice, but they claim it does inhibit rust.

chuckles wrote: I don't think WD-40 has much, if any, rust-prevention additives.

It does. It's one of my favorite rust preventers. For instance, milling machine table. Get it good and clean and then walk away for a week. BAM! Rusty. Do the same cleaning, and then mist it with WD40 before you walk away. 6 months later, that thing will still be pristine.

Tom Heath wrote:

chuckles wrote: I don't think WD-40 has much, if any, rust-prevention additives.

http://www.wd40.com/faqs/ I don't think its the ideal choice, but they claim it does inhibit rust.

I have pretty well hosed down two blocks and cranks with WD-40 and it didn't seem to work very well as a rust preventative.

big blocks need 40 gallons of fuel and it does not hurt them to carry around an extra hundred pounds of it. if he runs one tank he will be gassing up every other day.

DILYSI Dave wrote:

chuckles wrote: I don't think WD-40 has much, if any, rust-prevention additives.

It does. It's one of my favorite rust preventers. For instance, milling machine table. Get it good and clean and then walk away for a week. BAM! Rusty. Do the same cleaning, and then mist it with WD40 before you walk away. 6 months later, that thing will still be pristine.

Weird. In my firearms training and techniques class we were always instructed to stay away from WD-40. On a gun barrel they used gun oil, aer0-kroil and WD. Sure enough, the WD barrel has specs of rust the next week.

If he is regularly driving the truck, he can alternate tanks without filling both. He's currently got Tank A filled. When that one runs low, he fills up Tank B and leaves Tank A low. When Tank B runs low, he fills up Tank A and leaves B low. He's not out the extra money for storing gas in an unused tank, he's keeping all the mechanical parts working, and the fuel will help prevent rusting. If he's currently under the sea somewhere and is not driving the truck, then just ignore me.

Bob

Schmidlap wrote: If he is regularly driving the truck, he can alternate tanks without filling both. He's currently got Tank A filled. When that one runs low, he fills up Tank B and leaves Tank A low. When Tank B runs low, he fills up Tank A and leaves B low. He's not out the extra money for storing gas in an unused tank, he's keeping all the mechanical parts working, and the fuel will help prevent rusting. If he's currently under the sea somewhere and is not driving the truck, then just ignore me. Bob

Nope, not going to ignore. Thanks to all for your help. After a bit of a discussion, we came to exactly the suggestion above. It'll keep both fuel senders, filtes, lines, etc...stuff, moving and prevent gumming up of the tanks/lines.

When he's on a six month deploy, both tanks will be topped off, and appropriate amount of Stabil added to the fuel.

He'll be leaving for the state of Washington in January, and will need a co-driver. It should be fun.
--Thanks, Bob

If its a big block it wont know it has a little extra fuel. Fill them both, and as a bonus if he is short on cash he can run the next tank down as well. He gets paid on the 1st and 15th every month. He will be better off this way trust me.

triumph5 wrote:

Schmidlap wrote: If he is regularly driving the truck, he can alternate tanks without filling both. He's currently got Tank A filled. When that one runs low, he fills up Tank B and leaves Tank A low. When Tank B runs low, he fills up Tank A and leaves B low. He's not out the extra money for storing gas in an unused tank, he's keeping all the mechanical parts working, and the fuel will help prevent rusting. If he's currently under the sea somewhere and is not driving the truck, then just ignore me. Bob

Nope, not going to ignore. Thanks to all for your help. After a bit of a discussion, we came to exactly the suggestion above. It'll keep both fuel senders, filtes, lines, etc...stuff, moving and prevent gumming up of the tanks/lines. When he's on a six month deploy, both tanks will be topped off, and appropriate amount of Stabil added to the fuel. He'll be leaving for the state of Washington in January, and will need a co-driver. It should be fun. --Thanks, Bob

Yup, you're on to something here...This is about the best of the ideas. Have fun on the drive over, and tell him to keep his head down. The world needs those love big trucks.

First thing that poped into my mind was figuring a way to fill it with a inert gas, like welding inert gas or nitrogen.

But im sure there are easier ways, as mentioned.

The phosphoric acid based anti-rust that body shops use? (Ospho?)