Why is a full gas tank supposed to keep the fuel lines from freezing?

[tirwin]

I realize this isn't a purely 911 question but there is nobody better to ask...

Hotlanta is about to turn really cold. We're supposed to get single digit temps tomorrow (Tuesday) night of 5F which is just crazy for us. North Alabama is supposed to have a wind chill of -30F. I don't know if I can remember this kind of cold.

The local news just said any vehicles parked outside should have a full tank of gas to keep the fuel lines from freezing. My wife and I looked at each other puzzled. I've never heard anything like that before. Can any of you folks in the great white north that are more familiar with the effects of bone-chilling cold on engines explain the logic behind that recommendation? The only thing I can think is that with less fuel in the tank there is more air. I guess any water vapor in the air in the tank would condense and mix with the gas?

P.S. While the 911 is tucked safely in the garage, my truck is outside (with a full tank of gas).

[mikesride]

More fuel means less air in the tank.....less air in the tank means less condensation.
So your right.

[rwest]

Another benefit of a full tank, is if you get stuck somewhere, you can keep warmer longer.

[Canada Kev]

Originally Posted by mikesride

More fuel means less air in the tank.....less air in the tank means less condensation.
So your right.

Yep, that's it.

[tirwin]

Both make sense. I guess I was thinking the fuel lines would be pressurized at least for some period of time, so there wouldn't be much condensation. Most schools and businesses are closing tomorrow. When the liquid precipitation turns solid, we lose our minds.

[RDM]

It's not going to get cold enough for the gas to freeze, but a larger mass of gasoline would make the tank take longer to cool down. It's the water in the alcoholic gas and in the air that's the enemy.

[boyt911sc]

Tim,

It would take a lot more to freeze gasoline. For example, I have a gasoline container in my backyard for the snow blower and I leave it there during the winter time. The freezing point of a typical gasoline is between -40°F and -50°F. I would worry more about my water lines first than the car. The minus degree temperature you are getting in Atlanta is probably the wind chill factor not the ambient temperature. At any rate, hope you are not planning to drive the car in this weather.

Tony

[theiceman]

Actually for us in the great white North gas lines freezing isnt too much of an issue . as A rule winter has much drier temperatures and very low humidity .. So as a rule this isnt really an issue . you want gas in the tank because it is easier to freeze a staw full of anything than a bucketfull.

In typically humid areas where the temperature suddenly drops .. NOW you have aforementioned fuel line freezing due to humidity. you can always drop in some gas line antifreeze but can't see it being generally available in normal warm climates.

As mentioned i would be more woried about the coolant quality that is normally overlooked in warmer climates..

[tirwin]

Thanks, Tony. I wasn't worried. Just curious. Never heard that before. You know how the news makes things sound so dramatic. I was just wondering if there was any real technical basis for the recommendation. For the record, I had just filled up the truck by chance.

The minute there is even the slightest HINT of snow or really cold weather, the grocery stores sell out of bread and milk. Pictures like this are all over the news:



It is really amusing. Never sell out of anything else. Just bread and milk. We always joke that it is an elaborate plot by bread makers and dairy farmers. I don't know about you guys, but if I'm going to be trapped indoors with my family for a few days with no ability to go anywhere or do anything, I'm hitting the beer aisle!

It is cold outside today but it's just cold (23F). And the schools and businesses are all closed. That's how we roll in the ATL. You guys up north would laugh at us.

[Uncle Enzo]

Wait. 23 degree weather closed school and businesses? That's amazing. I would just sit inside and eat a loaf of bread.

[GH85Carrera]

Around here bad weather makes people want to buy the "Three Whites" milk, bread & toilet paper.

I guess everyone runs home to make French toast and that gives them diarrhea. I have never understood it. Especially the need to buy bread.

Gas freezes at -40 to -50 depending on the exact conditions and additives of the gas. Alcohol freeses at well below that. Just the water in the E-10 gas is the problem. We are lucky around here. I can buy 100% gas easily.

Stay warm!

[mikesride]

Originally Posted by tirwin

Thanks, Tony. I wasn't worried. Just curious. Never heard that before. You know how the news makes things sound so dramatic. I was just wondering if there was any real technical basis for the recommendation. For the record, I had just filled up the truck by chance.

The minute there is even the slightest HINT of snow or really cold weather, the grocery stores sell out of bread and milk. Pictures like this are all over the news:



It is really amusing. Never sell out of anything else. Just bread and milk. We always joke that it is an elaborate plot by bread makers and dairy farmers. I don't know about you guys, but if I'm going to be trapped indoors with my family for a few days with no ability to go anywhere or do anything, I'm hitting the beer aisle!

It is cold outside today but it's just cold (23F). And the schools and businesses are all closed. That's how we roll in the ATL. You guys up north would laugh at us.

Its cold up here again today....-43c (-45.5F)....but I wouldn't laugh at you over your situation. Cold is something we are used to, our bodies are somewhat acclimatized to it.
I've been to S Carolina in the summer and I cant figure out how you guys in those climates don't melt away!!!!!!
Stay warm.

[tirwin]

[widgeon13]

We will have a swing of 40+ degrees in upstate NY (45 to -1) and all the years I've lived here never had a problem with frozen fuel lines in this kind of weather. Perhaps if the car sat for extended time but not with daily driving to my experience.

[timmy2]

I lived in Manitoba for 35 years, supposed to be -50C this week there with the wind chill... It is the water in the tank and lines that freezes. We used to get bad fuel from underground tanks that would leave you stranded until you added some isopropyl. (Gas line antifreeze)

[tirwin]

Originally Posted by mikesride

Its cold up here again today....-43c (-45.5F)....but I wouldn't laugh at you over your situation. Cold is something we are used to, our bodies are somewhat acclimatized to it.
I've been to S Carolina in the summer and I cant figure out how you guys in those climates don't melt away!!!!!!
Stay warm.

That is just ridiculous cold! I don't know how you stand it. Atlanta is too far north for me. I would rather be hot than cold. A buddy of mine is the opposite. His logic is if he's cold he can always put on another layer of clothes but if he's hot, he can only get naked.

(In the south there are two different words for not having any clothes on. "naked" just means you don't have any clothes on. For example, when you are getting a doctor's exam. "nekkid" means you don't have any clothes on and you're up to something. "They got nekkid and slipped into the pool at the hotel when they thought nobody was around.")

[tirwin]

Originally Posted by widgeon13

We will have a swing of 40+ degrees in upstate NY (45 to -1) and all the years I've lived here never had a problem with frozen fuel lines in this kind of weather. Perhaps if the car sat for extended time but not with daily driving to my experience.

Bingo. That was my suspicion!

[BeeMaster]

23 F? we have a high of -13f here today. Wind chill -30f to -50 f. The other reason you should have a full tank Of fuel is for weight over the back axel ( in most cars) for traction in snow.

[manbridge 74]

It is convenient that the fuel level sending unit can be removed to check for water buildup on tank bottom. Slightly jack up the right side of car and you can suck it out using an extractor.

[tirwin]

Originally Posted by manbridge 74

It is convenient that the fuel level sending unit can be removed to check for water buildup on tank bottom. Slightly jack up the right side of car and you can suck it out using an extractor.

Great tip!