New Gas Tank in Car - Put Gas In or Leave It Dry

[bill pritchett]

Here in NJ, I have a friend/neighbor who just put a new gas tank in his 1986 Mustang.  He stores it in his house garage which is unheated.  The question is should he put ethanol free gas in it for the winter or leave it empty until spring.  The question is which is worse for moisture.  It runs and drives, but just got it done prior to it getting close to winter.  It is supposed to be a closed system with the original emissions intact.

 

Thanks for your input.

Edited November 30, 2023 by bill pritchett (see edit history)

[31Buick96S]

I’d lean towards leaving it dry, on the theory that they sit around in warehouses until they’re sold with no issues. Gas is too unstable these days.

[yachtflame]

I used to leave the country for 8 months a year. When I got ready to leave, I would fill the tanks with a 20/1 diesel an oil mixture, then drain it. That would keep my gas tanks rust free without any danger of igniting when draining. The engine will run a bit smoky for the first tank but won’t hurt anything. If your friend heats his house by oil, just add the drainage to the oil tank. 

[Frank DuVal]

If not driving for months, then leave it dry until ready to drive it for the season.

[TAKerry]

I hope the answer is leave it dry. Thats how my new tank has been for the last couple of years in my car. 

[DFeeney]

I would be more worried about the "New gas" going bad than rust damage to the tank.  If it's under restoration in your shop I would drain it and leave it dry.

[Jack Bennett]

A 1986 model car is a bit newer than my experience with old cars goes.

But, since it is not a primary transportation car, storing it like a old car is also acceptable.

I do not like having gas, especially in a vented car tank, around my furnace or water heater. Also, the price of gas makes watching it evaporate a pass time as expensive as driving the car.

I have the 2 1/2 gallon tank, scavenged from a pancake air compressor, converted to a small, easily transportable and storable gas tank for periodic use on my cars. 
If the Mustang has EFI or a in tank fuel pump this may be a problem, but I have a connector directly attached to the carburetor fuel line whereby I just add gas to the small tank, connect it to the cars fuel line, and after running/moving the car, disconnect the hose from the jump tank, and chill.

Jack

Edited November 30, 2023 by Jack Bennett (see edit history)

[Jack Bennett]

A 1986 model car is a bit newer than my experience with old cars goes.

But, since it is not a primary transportation car, storing it like a old car is also acceptable.

I do not like having gas, especially in a vented car tank, around my furnace or water heater. Also, the price of gas makes watching it evaporate a pass time as expensive as driving the car.

I have the 2 1/2 gallon tank, scavenged from a pancake air compressor, converted to a small, easily transportable and storable gas tank for periodic use on my cars. 
If the Mustang has EFI or a in tank fuel pump this may be a problem, but I have a connector directly attached to the carburetor fuel line whereby I just add gas to the small tank, connect it to the cars fuel line, and after running/moving the car, disconnect the hose from the jump tank, and chill.

Jack