Gassing up while the tanker is present

[rationull]

Is this really a problem?

I've heard the standard internet myths about it being a bad thing to fill your gas tank while the tanker truck is there filling up the station's underground tanks. I can see the logic but I wonder if there's actually anything to it.

 

[TomYoung]

Why risk it?

 

[Bottom_Feeder]

What exactly is risky about this?

 

[rationull]

Couldn't have had a better first two responses

The theory is that filling the underground tanks will kick up sediment and water in the underground tanks which will then be pumped into the car.

As to "why risk it?" I think the answer depends on whether or not it's actually a problem.

 

[BigBuck]

I have never had an issue with it. It has happened to me several times. It probably mixes up the additives in the gas too. That, and fresher gas for you. I am sure your fuel filter will catch most of anything that will cause harm.

 

[Astro14]

Was with my Dad during the gas crisis of '73-'74 when he filled up his VW while the tanker was filling the station tanks. Car died a mile later and wouldn't start.

Cause was water in the gas.

Coincidence?

 

[roadrunner1]

I know of a guy who was filling up his Dodge 5.9 Cummins while the tanker was filling up the underground tank. He made it about five miles down the road before a complete failure occurred in his fuel system.
He was able to get the station to pay through his insurance company.

I don't know the exact details of what caused the catastrophic failure, but the entire fuel system needed replaced, including the tank to the injectors.

It may have helped his case being an engineer at Dodge his first step was to go back to the station with his receipt in hand that was time-stamped and obtained a copy of the delivery receipt, so he had solid evidence he was fueling at the same time as they were receiving fuel.
His second step was get a sample of fuel from the station to compare with the fuel analyzed from his truck at an accredited lab for definitive proof that the station was at fault.

It all worked out in the end and he still has the truck, but the grief involved getting everything straightened out definitely was not worth it.

 

[opus1]

If I see the tanker, I drive on. Period.

Had a conversation along these lines with a friend once. Long story short, his premise was that one may pull into the station 2 minutes after the tanker left, have no way of knowing that, and get the same stirred-up gas as one would get while fueling while it was there. My response was that while it may be true, how often is that going to happen? One thing I *do* know is that if the tanker is there, I will get the melange every time and that is something I can control by driving on.

 

[Hokiefyd]

I've done it numerous times without issue. And as long as you're at a modern service station with modern tanks, there shouldn't be an issue. Modern fiberglass/plastic tanks don't have sediment at the bottom as older steel tanks may have had, and there should be very little water sitting at the bottom of these tanks to get mixed with fuel. Small enough, anyway, that when diluted across the typical 12,000 or 15,000 gallon storage tank capacity, it will not be an issue for your car.

 

[scurvy]

Originally Posted By: rationull
Is this really a problem?


Hard to say - after all, the fuel pumps are supposed to have filters on them.

I can say that I once asked a tanker driver what he was about to dump in order to avoid filling up my Golf while fresh fuel was going into the tank. He said that it was safe to use the diesel pumps as he had just started delivering gasoline but had not yet hooked up to the diesel compartment of the tanker.

The unspoken message being that he would not fill a vehicle's tank while a tanker truck was delivering fuel.

While I think the risk of anything bad happening is small, there is still a greater risk of filling up while the tanker truck is in the process of dumping fuel or shortly thereafter.

Originally Posted By: Bottom_Feeder
What exactly is risky about this?


Just to expand on rationull's post, underground tanks are not spotless, pristine examples of shining white-glove cleanliness. There's rust, scale, debris, dead pigeons, water, Jimmy Hoffa's skeleton and who knows what else down there, but most of that is resting gently at the bottom of the tank below the pump's standpipe. When the tanker truck delivers fuel, it's not gently lowered down and laid to rest with all the other fuel, it's literally dumped right into the tank which stirs up all the detritus mentioned above. So now you have a small (but growing) volume of fuel that has years of accumulated flotsam being churned around.

Some say that filling up while this is happening means you are far more likely to suck some of that muck up through the pump standpipe than if you fill up while a tanker isn't dumping fuel - and I have to agree. But how much of that would actually make it into you tank...

Life is all about managing risk. It's easy enough for me to keep on driving to the next station or fill up the next day, so I try to make a point to pass on by.

 

[TallPaul]

Problem is that you pull in to the gas station and don't know if the tanker just left less than 5 minutes ago. If there is water in the tanks, would it still be stirred up from the filling activity after 5 minutes settling time?

 

[mechtech2]

Originally Posted By: rationull
Is this really a problem?

I've heard the standard internet myths about it being a bad thing to fill your gas tank while the tanker truck is there filling up the station's underground tanks. I can see the logic but I wonder if there's actually anything to it.


If you can see the logic, then why all them myths??

 

[Hokiefyd]

Originally Posted By: scurvy
There's rust, scale, debris, dead pigeons, water, Jimmy Hoffa's skeleton and who knows what else down there, but most of that is resting gently at the bottom of the tank below the pump's standpipe.


While it may be the safer play to assume that all tanks are like this, the reality is that most underground storage tanks today ARE very clean inside. You can usually tell just by looking at the service station if they're still using old steel tanks; I doubt anyone aware of the situation enough to be on BITOG would be filling there anyway. Most all of your more modern stations (Exxon, Shell, Valero, BP, Walmart, Sams, Costco, etc) are using modern double-wall fiberglass-reinforced plastic tanks. They have monitoring systems that indicate water in the tank. The station has an incentive to remove the water; it's less fuel they can sell.

This is one of those things that probably used to be an issue 30 years ago, but just doesn't exist to much, if any, degree today. It certainly doesn't hurt to simply drive to the next station, though.

It's like Mobil vs. Pennzoil (or whatever one's favorite brands are). Whatever helps you sleep at night!

 

[HerrStig]

Originally Posted By: Astro14
Was with my Dad during the gas crisis of '73-'74 when he filled up his VW while the tanker was filling the station tanks. Car died a mile later and wouldn't start.

Cause was water in the gas.

Coincidence?
More likely that the station tank was at the very BOTTOM at the time, where all the crud resides. Water is heavier than gas.

 

[Hokiefyd]

Originally Posted By: TallPaul
Problem is that you pull in to the gas station and don't know if the tanker just left less than 5 minutes ago. If there is water in the tanks, would it still be stirred up from the filling activity after 5 minutes settling time?


In stations selling an ethanol blend, there is not likely to be a phase separation, meaning the water and gasoline likely aren't sparate anyway. A 12,000 gallon tank of 10% ethanol would have to have 36 gallons of water in it for phase separation to occur. I'm not saying that it can't happen, but that volume of water is unlikely in a station equipped with modern systems.

Now, if you're talking about Billy Joe's 76 station that you worked at as a kid and still operates on the original tanks and original pumps? That's a different story.

 

[rshaw125]

Seems like most of the time I go to Costco for gas a tanker truck is there. Maybe this problem existed decades ago but not now. The gas at Costco is fresh coming up the pipeline from the Gulf coast. Filtered as I pump it into my car. 5 years now of using it not even a sputter from my cars.

As for old style tanks. I thought they all had to be replaced over 10 years ago?

 

[ARCOgraphite]

You are getting E10 loaded with water all the time. Sometimes it separates (need less than 1% water) and you could get only E95 + water with NO GASOLINE. This has happened to me more than a few times last year - one more time and the Fit will be dead. If you run light throttle/ low rpm, a wideband o2 front sensor will comp for E95 but there is not enough mass fuel flow on a gas fuel engine to allow even 1/2 throttle at mid range (3500-4500) rpm without severe lean out. I managed a station in the 70's and there was always a few inches of water in the tank - That has to be 100s of gallons.

 

[d00df00d]

Originally Posted By: mechtech2
If you can see the logic, then why all them myths??

Because some of us have the humility to understand that what seems to make sense to us may not actually be real, and thus we need real evidence to clinch something.

 

[Fleetmon]

Depends on whether the UST are "bottom-dropped or splash dropped...bottom-dropped means the fuel pipe goes near the bottom of the tank at about the same depth as the pick-up pipe which is typically about 24" or so above the bottom of a 20k gallon tank....this type of drop WILL cause sediment, water, rust, Hoffa's body and anything else at the bottom to get sucked up into the pick-up pipe. Splash drop means the fill pipe ends just inside the top of the tank and just splashes into the old fuel.

When I worked in the transit bus business, all of our fuel drops (manifolded bottom-drops x five 20k gallon tanks at each bus division)took place in the early AM (7AM) after the fueling operation ended for the day (3AM) and the diesel pumps were locked out for 4 hours to allow everything to settle. A transit system as large as ours typically received a minimum of 2 7.5k gallon drops per day at each bus division and 3-4 7.5k gallon drops on Fridays dependent on the tank levels. Annual diesel use typically exceeded 10M gallons to support a bus fleet that did about 30 million miles per year (extra fuel was stored just in case).

Most large tanks are also equipped with a Veeder-Root system or other form of electronic monitoring so you'll know when to suck out the "bad" stuff.....a lot of smaller places still use water paste that they dab on the end of their tank sticks to measure water depth.

Bottom line is you are taking chances if you fuel when a tanker is connected, especially with diesel (takes longer to settle). Most tanks are also bottom-drops to minimize foaming with diesel to prevent the foam from coming out of the vent. If you ask what type of tanks most stations have though they'll look at you strangely....not unlike how your wife/kids/neighbors look at you when you start talking about engine oils and grease.

ARCOgraphite is correct....pumping several inches of water/junk from the bottom of a 20k gallon tank will easily fill 4-5 55 gallon drums. Those that haven't had problems are just plain lucky....me? I don't fill if I see a tanker hooked up and yes, I know, I don't know if a tanker just left but 98% of the time I fuel my BMW diesel at the same place and around the same time.

 

[Bottom_Feeder]

So I guess I'm the only one assuming that gasoline is filtered as a) it leaves the storage tank, and/or b) it leaves the pump?