Adjusting fuel temp. on gasoline - Diesel Forum

OT · 09-15-2009, 07:13 PM

Got notice of action against Costco saying "Costco misled consumers by marketing motor fuel at temps above 60deg F. without adjuisting for the fuels temp" If settlement reached..only action taken will be "auto. temp. correcting pumps will be installed" About 25 states listed. Here's my Q.

What is a auto. temperature correcting pump & what does it do? Never heard of this before. Anyone know? TIA

chuckster57 · 09-15-2009, 07:29 PM

Good reading here:

'Hot Fuel' Adds To Pain At The Pump - Consumer Watchdog

OT · 09-16-2009, 10:53 AM

Well..that answered my Q. Tks. Sometimes I think maybe I'd be better off not knowing..was doing just fine till I got notice.

drcampbell · 09-16-2009, 11:24 AM

Except that you were being shortchanged ...

OT · 09-16-2009, 01:42 PM

Short changed..apparently so. Part about expansion/contraction (link) Warm VS cold. Do we get more fuel when cold?

Possible..Pro's/Con's..We get what we pay for yr. round OR we pay extra yr. round due to cost of new pumps? Not all states listed which make's me wonder why not?

drcampbell · 09-17-2009, 07:09 AM

Quote:

Originally Posted by OT

... Do we get more fuel when cold?

If the pump says it dispensed a gallon of fuel, you received a gallon of fuel. But if it's warm, the fuel has expanded and there's less fuel in that gallon - fewer hydrogen and carbon atoms, fewer kilograms.

Quote:

Originally Posted by OT

... Possible..Pro's/Con's..We get what we pay for yr. round OR we pay extra yr. round due to cost of new pumps? Not all states listed which make's me wonder why not?

One reason might be that there aren't Costco filling stations in all 50 states. It's not going to be an issue in Hawaii because of the constant temperature and a pre-existing requirement that pumps be calibrated to 80 degrees. Temperature compensation has probably already been installed in northern states, where the retailer comes out ahead. And in some state Bureaus of Weights and Measures probably already require it, in places where the prevailing attitude favors stronger government.

But don't fall for the argument that the cost will be passed down to the consumer. The retail price of gasoline - or any other commodity - is set by market conditions, not the by cost of doing business. If the station across the street drops the price by a dime, you have to match it regardless of how much you've invested in new pumps.

And don't assume the cost is significant. Just how much gas do you think a filling station pumps in a year's time? It amortizes pretty fast.

LMJD · 09-17-2009, 09:05 AM

Quote:

What is a auto. temperature correcting pump & what does it do? Never heard of this before.

Me neither, sounds like a newly formed gov't agency on a mission to justify their jobs. First, all the tanks are underground so the temp is going to stay fairly constant, winter or summer, right? Unless the theory has changed, house builders tell me that's why you have a 5' crawlspace or basement in cold country so your pipes stay in the constant 50 degree range. We can have weeks of near 100 degrees in summer or weeks of -20 degrees winter and my basement thermometer only varies by about 7 degrees. But the same doesn't apply to underground fuel tanks? Some are great people, but I've had the misfortune of working with a few gov't agency whacko zealots in the past. My Crap Detector's going off big-time.

chuckster57 · 09-17-2009, 09:14 AM

This whole thing about hot/cold fuel is something I have been aware of for at least 25 yrs. My kids mother will still only fuel up in the early A.M. when she says the gas is more dense. I asked the same thing- tanks are underground in a constant enviornment. Is it in the "pump" long enough to expand enough to really make a difference?

I for one think we should send the case to MYTHBUSTERS

LMJD · 09-17-2009, 01:58 PM

Quote:

This whole thing about hot/cold fuel is something I have been aware of for at least 25 yrs.

Oh me too and I never gave it a thought until guys (housebuilders) wised me up on the real reason deep crawlspaces and basements are necessary in real cold climates. Plus, seems like they had a feature on how gas station fuel tanks are made nowdays and they're double walled plastic/fiberglass? (wrong term). Don't know if you spent time around Kfalls, Malin, Oregon, but that's why you see so many underground spud cellars---keeps the spuds at an ideal constant temp. You're right, Mythbusters where are you??

drcampbell · 09-17-2009, 07:16 PM

Did you read the article? Particularly, the part where they measured the temperature of fuel delivered in California and found it consistently above the temperature the pumps are calibrated for? It's not about day-to-night or summer-to-winter variability.

It may be true that soil temperature is nearly constant, but that's not terribly relevant. The underground storage tanks at filling stations are so large (typically 25,000 gallons) that the surface area-to-volume ratio is very high, giving the soil temperature little influence on the fuel temperature. They're also emptied & refilled frequently, giving any given gallon of fuel little residence time for heat transfer, and modern tanks are double-walled, (for leak detection) providing an insulating air space between the fuel and the soil.