I use half tank of gasoline in my chevy 2014 pickup per month. Is it better to maintain it between full and half empty or between half empty and almost empty?

On 08/04/2016 2:32 PM, Frank Thompson wrote:
I use half tank of gasoline in my chevy 2014 pickup per month. Is
it better to maintain it between full and half empty or between half
empty and almost empty?

For what definition of "best", pray tell?

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On 8/4/2016 3:32 PM, Frank Thompson wrote:
I use half tank of gasoline in my chevy 2014 pickup per month. Is it better to maintain it between full and half empty or between half empty and almost empty?

I've always understood that running empty could cause a problem as gunk
may get into system. I usually fill my little SUV when half full and
never go below a quarter tank.

On 08/04/2016 2:49 PM, Frank wrote:
On 8/4/2016 3:32 PM, Frank Thompson wrote:
I use half tank of gasoline in my chevy 2014 pickup per month. Is it
better to maintain it between full and half empty or between half
empty and almost empty?

I've always understood that running empty could cause a problem as gunk
may get into system. I usually fill my little SUV when half full and
never go below a quarter tank.

The pump pickup is at the bottom, anyway...

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On Thursday, August 4, 2016 at 3:59:38 PM UTC-4, dpb wrote:
On 08/04/2016 2:49 PM, Frank wrote:
On 8/4/2016 3:32 PM, Frank Thompson wrote:
I use half tank of gasoline in my chevy 2014 pickup per month. Is it
better to maintain it between full and half empty or between half
empty and almost empty?

I've always understood that running empty could cause a problem as gunk
may get into system. I usually fill my little SUV when half full and
never go below a quarter tank.

The pump pickup is at the bottom, anyway...



I haven't had one apart, but unless it follows a float down or similar,
what you say is logical. The only advantage I see to not filling all
the way is reduced weight, but that isn't going to make much difference
in MPG.

I've always understood that running empty could cause a problem as gunk
may get into system. I usually fill my little SUV when half full and
never go below a quarter tank.

The pump pickup is at the bottom, anyway...


in pump tanks are kept cooler when covered

m

On 08/04/2016 3:05 PM, wrote:
....

in pump tanks are kept cooler when covered

The pump motor sits in a well/depression that can't be pumped dry for
that reason...at least on all those I've replaced and I presume they're
all designed that way.

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On 8/4/16 3:32 PM, Frank Thompson wrote:
I use half tank of gasoline in my chevy 2014 pickup per month. Is it better to maintain it between full and half empty or between half empty and almost empty?


Less likely to get water from condensation when it's full- plus if the
ball goes up, you're better off with a full tank.

--
Make America great again? Hell, I'd be happy if you just made it America
again.
- @KelsowFarlander

On 8/4/2016 3:32 PM, Frank Thompson wrote:
I use half tank of gasoline in my chevy 2014 pickup per month. Is it better to maintain it between full and half empty or between half empty and almost empty?


More full is always better. Fuel systems are better sealed these days
but condensation was always a consideration. Ethanol added helps in
that regard too.

I usually fill at 1/8 to 1/4 but have to fill up every 5 or 6 days so
nothing collects.

Fuel has been improved too with better additive packages and filtration.
If you use cheap unbranded gas, use a top tier every few fillups and
you will get some benefits.

if you run your tank dry, run out of gas it can and does damage the fuel pumps located in the tank. that can cost 600 bucks and more to drop the tank and install new pump


the pumps use the gasoline to cool the pump.

On 8/4/16 2:32 PM, Frank Thompson wrote:
I use half tank of gasoline in my chevy 2014 pickup per month. Is
it better to maintain it between full and half empty or between half
empty and almost empty?

Above half in the off chance you need to get somewhere in a hurry
with it.

On 8/4/2016 3:32 PM, Frank Thompson wrote:
I use half tank of gasoline in my chevy 2014 pickup per month. Is it better to maintain it between full and half empty or between half empty and almost empty?


Much depends more on the season. In winter, more than half to avoid
condensation which doesn't build up as much in the summer. Otherwise, I
don't think it makes much of a difference.

Every car I've owned (all pre 2000 models) was driven until the low fuel
indicator illuminated and I've never had a problem with pumps or
anything fuel related. That was also done all year long regardless of
weather here in Mich. I don't think it's as much of an issue as some
would think.

On 08/04/2016 03:32 PM, Frank Thompson wrote:
I use half tank of gasoline in my chevy 2014 pickup per month. Is it better to maintain it between full and half empty or between half empty and almost empty?


E-10 gasoline phase separation is your enemy.
Humidity, daily temperature swings and how well your fuel tank is sealed are big factors.
Will phase separation occur in your trucks tank? No one here can actually tell you.

Some theorize that keeping the tank full is better, some say it doesn't matter.
Some would suggest using ethanol-free gasoline.
Some would suggest using an additive like Sta-Bil.

If phase separation occurs, how much will the repair costs be for your truck?

How luck do you feel?

On 08/05/2016 4:04 AM, Joe wrote:
....

E-10 gasoline phase separation is your enemy.
....

Actual documented evidence of such over typical short durations between
tank fillings?

I've a number of vehicles that get intermittent use that sometimes go
several months and have never experienced such.

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On 08/05/2016 10:06 AM, dpb wrote:
On 08/05/2016 4:04 AM, Joe wrote:
...

E-10 gasoline phase separation is your enemy.
...

Actual documented evidence of such over typical short durations between
tank fillings?
....

Of fresh (uncontaminated) fuel in a vehicle tank, that is, certainly
it's possible owing to contamination in USTs and the like...

Well, let's see -- yeah, if I work out the volume of water entrained in
the 10 gal of a half-empty 20 gal tank assuming 100% RH @ 60F and 1
atm., I get it's roughly 1.3E-5 gal. The roughly 0.5% by volume
required for phase separation equates to 0.005 gal so fully saturated
air if all condensed to water would be only about 0.25% of that required
to cause phase separation.

I'm thinking it's a non-issue...

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On 08/05/2016 11:06 AM, dpb wrote:
On 08/05/2016 4:04 AM, Joe wrote:
...

E-10 gasoline phase separation is your enemy.
...

Actual documented evidence of such over typical short durations between tank fillings?

Why don't you google it?

I've a number of vehicles that get intermittent use that sometimes go several months and have never experienced such.


As the OP stated, it all depends on humidity, daily temperature swings and how well the tank is sealed.
Personally I wouldn't worry about it and if I did, I'd use ethanol free gas.

On 08/05/2016 1:56 PM, Jake wrote:
....

As the OP stated, it all depends on humidity, daily temperature swings
and how well the tank is sealed.
Personally I wouldn't worry about it and if I did, I'd use ethanol free
gas.

See the follow-up; the point was asking if OP had any evidence of it in
a vehicle, _NOT_ in UST or thru deliberate or accidental introduction of
water but by condensation.

I went ahead and did some calc's; it's essentially impossible starting
from uncontaminated fuel to introduce sufficient water volume that way.

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On 08/05/2016 03:04 PM, dpb wrote:
I went ahead and did some calc's; it's essentially impossible starting from uncontaminated fuel to introduce sufficient water volume that way.


Thanks but I think I'll believe the real experts.

http://www.lcbamarketing.com/phase_s...hanol_blen.htm

posted for all of us...




I've always understood that running empty could cause a problem as gunk
may get into system. I usually fill my little SUV when half full and
never go below a quarter tank.

The pump pickup is at the bottom, anyway...


in pump tanks are kept cooler when covered

m

Actually the fuel is circulated through the pump to cool it.

--
Tekkie

On 08/05/2016 2:55 PM, Jake wrote:
On 08/05/2016 03:04 PM, dpb wrote:
I went ahead and did some calc's; it's essentially impossible starting
from uncontaminated fuel to introduce sufficient water volume that way.


Thanks but I think I'll believe the real experts.

http://www.lcbamarketing.com/phase_s...hanol_blen.htm

Well, I'm not positive they're really experts; the following white paper
says they're using a factor of 10X too low for the solubility/phase
separation point--0.05% vis a vis 0.5%. I'm inclined to believe the
latter over the former as being "more expert".

Even if the former were correct, it's still only 2.5% of the saturation
volume in 100% RH air if were to condense it all. I'd be willing to
listen if somebody could recompute independently and show gross error in
the above estimate.

If it were such a problem as the above reference claims, it'd be
happening all over the US in such high numbers there'd be no way the
issue couldn't be addressed. I think they're simply over-reacting to
the possibilities of clean fuel contamination. _Getting_ contaminated
fuel from a service station, otoh, does happen fairly regularly owing to
water entrance into USTs by various mechanisms or other ways of
introducing water in bulk into supplies. But starting with clean fuel
in a vehicle tank from condensation? Nah, ain't agonna' happen...

http://www.veeder.com/gold/download.cfm?doc_id=6935
(PDF DOC link to a readable white paper on the subject by vendor of
prevention/mitigation systems for bulk suppliers)

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On 08/05/2016 2:55 PM, Jake wrote:
On 08/05/2016 03:04 PM, dpb wrote:
I went ahead and did some calc's; it's essentially impossible starting
from uncontaminated fuel to introduce sufficient water volume that way.


Thanks but I think I'll believe the real experts.

http://www.lcbamarketing.com/phase_s...hanol_blen.htm

Well, as noted before, I wasn't convinced by their analysis having done
the calculation so I kept looking and found another white paper; this
one by EPA

It draws the same conclusions I did--

"Phase separation, however, generally only occurs when liquid
water (as opposed to water vapor) is introduced to the fuel
system. If tank vents are left open, either in the engine being
operated, or at a fuel distribution station, water can enter the
fuel system in the form of rain (or spillage, etc.) or through
the air in the form of moisture. Also, since conventional
gasoline absorbs very little water, there is often a layer of
water present at the bottom of a filling station tank normally
used to store conventional gasoline (water is more dense than
gasoline, and will therefore sink to the bottom). Before an
oxygenated gasoline is added to such a storage tank for the first
time (particularly ethanol-blended fuels), this water must be
purged from the tank to prevent the water from removing any
ethanol from the fuel.

Since the solubility of water in both gasoline and air
decreases with a decrease in temperature, water can enter a fuel
system through condensation when the atmospheric temperature
changes. For example, assume a tank containing conventional
gasoline contains only one gallon of fuel. Assume also that it
is closed while the outside temperature is 100 degrees F with a
relative humidity of 100 percent. If this tank is left sealed
and the temperature drops to 40 degrees F, water will likely
condense on the inside of the tank, and dissolve in the fuel. In
order for enough water to condense from the air to cause
gasoline-water phase separation, however, there must be
approximately 200 gallons of air per gallon of fuel over this
temperature drop (100 to 40 degrees). Since oxygenated fuels can
hold even more water than conventional gasoline, it is even more
unlikely that enough water will condense from the air to cause
gasoline-water phase separation."

The 200:1 ratio almost precisely duplicates my earlier estimate...I just
quoted it over a differing volume and in alternate units. I did note
that while I hadn't computed it, the 3.8 tsp measurement your reference
used is referred to in this document but they mis-computed/mis-typed the
percentage in the 0.05%; it is 0.5%.

So, anyway, the problem of phase separation in E10 of initially clean
fuel in a clean tank occurring owing to moisture condensation from the
air introduced alone is simply a non-issue.

http://www.epa.gov/sites/production/files/2015-09/documents/waterphs.pdf

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On Thursday, August 4, 2016 at 3:32:40 PM UTC-4, Frank Thompson wrote:
I use half tank of gasoline in my chevy 2014 pickup per month. Is it better to maintain it between full and half empty or between half empty and almost empty?

just have the fuel pump in your gas tank die because you have run it dry too often, cost 600 bucks and up/

and if your intelligent you will keep tank mostly full

bob haller wrote:
On Thursday, August 4, 2016 at 3:32:40 PM UTC-4, Frank Thompson wrote:
I use half tank of gasoline in my chevy 2014 pickup per month. Is it better to maintain it between full and half empty or between half empty and almost empty?
just have the fuel pump in your gas tank die because you have run it dry too often, cost 600 bucks and up/

I replaced mine myself on my 1969 Buick pretty cheap. Have they changed
that much in 47 years?




and if your intelligent you will keep tank mostly full

On Saturday, August 6, 2016 at 9:27:44 PM UTC-4, Bill wrote:
bob haller wrote:
On Thursday, August 4, 2016 at 3:32:40 PM UTC-4, Frank Thompson wrote:
I use half tank of gasoline in my chevy 2014 pickup per month. Is it better to maintain it between full and half empty or between half empty and almost empty?
just have the fuel pump in your gas tank die because you have run it dry too often, cost 600 bucks and up/

I replaced mine myself on my 1969 Buick pretty cheap. Have they changed
that much in 47 years?




and if your intelligent you will keep tank mostly full

minimum price for a aftermarket in tank pump assembly 300 to 400 bucks.

for a brand new OEM pump at least 600 bucks and often more. pumps include fuel gauge and fuel filter. the gasoline in the tank cools the pump. run the tank low or out, espically in hot weather, fries the pump.......

my 1969 impala had a fuel pump fail, a easy replacement bolted to the engine.. i think it cost 40 bucks

far cheaper to always keep the tank at least half full.

but its your money and your back, feel free to replace them as often as you want..........

On Sun, 7 Aug 2016 08:52:46 -0700 (PDT), bob haller
wrote:

On Saturday, August 6, 2016 at 9:27:44 PM UTC-4, Bill wrote:
bob haller wrote:
On Thursday, August 4, 2016 at 3:32:40 PM UTC-4, Frank Thompson wrote:
I use half tank of gasoline in my chevy 2014 pickup per month. Is it better to maintain it between full and half empty or between half empty and almost empty?
just have the fuel pump in your gas tank die because you have run it dry too often, cost 600 bucks and up/

I replaced mine myself on my 1969 Buick pretty cheap. Have they changed
that much in 47 years?




and if your intelligent you will keep tank mostly full

minimum price for a aftermarket in tank pump assembly 300 to 400 bucks.

for a brand new OEM pump at least 600 bucks and often more. pumps include fuel gauge and fuel filter. the gasoline in the tank cools the pump. run the tank low or out, espically in hot weather, fries the pump.......

my 1969 impala had a fuel pump fail, a easy replacement bolted to the engine.. i think it cost 40 bucks

far cheaper to always keep the tank at least half full.

but its your money and your back, feel free to replace them as often as you want..........

I've replaced a few, one last year. That one was an Bosch for
$142.50. They have never cost me much more than that.
You might pay $600 for shop to drop the tank and replace.

On Thu, 4 Aug 2016 12:32:35 -0700 (PDT), Frank Thompson
wrote:

I use half tank of gasoline in my chevy 2014 pickup per month. Is it better to maintain it between full and half empty or between half empty and almost empty?
Keep tank top half full. Keeps out air and possible condensation. Not
as critical on a properly functioning late model, but still adviseable

On Thu, 4 Aug 2016 22:44:04 -0400, Meanie
wrote:

On 8/4/2016 3:32 PM, Frank Thompson wrote:
I use half tank of gasoline in my chevy 2014 pickup per month. Is it better to maintain it between full and half empty or between half empty and almost empty?


Much depends more on the season. In winter, more than half to avoid
condensation which doesn't build up as much in the summer. Otherwise, I
don't think it makes much of a difference.

Every car I've owned (all pre 2000 models) was driven until the low fuel
indicator illuminated and I've never had a problem with pumps or
anything fuel related. That was also done all year long regardless of
weather here in Mich. I don't think it's as much of an issue as some
would think.
The top quarter doesn't cost any more than the bottom quarter.