condensation
 

I was reading some discussions on condensation and am inclined to add my experience with putting a new fuel tank /sending unit in my 1996 Chevy truck. After installing the tank and adding 5 gallons of fresh fuel I pulled my truck out of a heated garage (app. 50-55 degrees) and (app.20 degrees outside temp). I plowed snow with it and parked it for the evening. The next day it would not start. After try either to no avail I pushed it back in the garage and added a red bottle of heat (isopropyl alcohol). Several hours later it started right up. I must assume that it was due to condensation as I have not had problems with water in the fuel prior to this.
I can see where keeping the fuel tank full may help, but who keeps their fuel tank full all of the time. My thoughts are that someone who parks their vehicle in a heated garage subjects themselves to this problem on a daily basis, ergo is it even practical to use a heated garage?

Ethanol is a cosolvent that allows gasoline to absorb much more water in solution before the ethanol-water blend drops to the bottom, and the ethanol also reduces the freezing point, so I doubt if the HEET did much good. Getting it back into the warm garage was what unfroze the water or water-alcohol blend.

Modern fuel systems are "closed" and the tank can build up to about 2 psi pressure or vacuum before the relief valve opens, but if you have a half tank of fuel and move from a warm (especially with high humidity) to cold environment, there could be some condensation that caused the drop out and freezing.

E10 must be handled carefully to avoid water absorbtion. That's why E10 is not shipped in pipelines. Only the gasoline component is shipped in pipelines to distribution centers. The ethanol is delivered in tanks cars (rail or truck) and blended with the gasoline as the truck that distributes the fuel to the retailer is filled, but despite the care that the industry takes to prevent water contamination, it can still happen in isolated cases.

I had a fuel freeze situation once in my life in Seattle back in the mid-sixties during a cold spell. There was no garage to put the car in, so I just let it sit until the weather warmed up, and it started. Of course, the car had a vented fuel system and fuel freeze-ups were more common back then than with modern sealed fuel systems.

Duke