Do you fill your gas tank to the nearest full dollar?

Could this really damage your car or truck?

Dave Cohen, WWL First News early edition
January 16, 2019 - 7:46 am

We were talking about gas prices today and what it costs to fill the tank.  That led to a conversation about how many of us like to keep pumping gas into our vehicles' tanks until the pump reads a nice, round number.

Like if the pump shuts off at $35.78, I will squeeze another .22 cents into my tank to make the total $36.00.

News Anchor David Blake said he goes into the store and buys a few items and then "does the math" to make the total of his purchases and his gas hit an event total.  So, if he is buying $6.87 worth of stuff... he will then get $18.13 in gas to make his total an even $25.00.

Listeners started chiming in with even more behaviors like this.

One explained how they fill the tank with just enough gas to leave their bank account at an even number.

"Oh, I take it another step. I check the balance of my checking account and then I pump the gas to the exact amount to give me an even number in my checking account," the listener explained in a text to 870870.

Others told how missing the mark can ruin their day.

"Just pumped $40.01, now I have to live with that all day," one person texted.

Here are some more listener comments:

  • I do the same thing with fueling up, rounding up to that next dollar, trying to get to $30.00 or whatever. I try so hard I make the mistake of PASSING IT UP and it be $30.01. Then I'll try to get to $31.00 lol
  • I used to try to end with a rounded up number at the gas pump until I learned that over filling your tank can damage your car.
  • I end my gas at the nearest Quarter. .00 / .25 / .50 / .75
  • I thought I was the only anal one to even up at the pump!
  • Dave: I do the same thing when I pump gas.
  • I even my fill up as well
  • If you lived in Michigan here in the winter you don't care what numbers pop up on that pump. You just want to get back in your car!
  • Never round up...the sooner the pump stops taking my money the merrier!!
  • When filling the gas tank, I do the Jerry Seinfeld "release the hounds" bit
  • I always stop on a 1 so my wife knows it's my vehicle being filled to keep track of my fuel usage
  • That started when we balanced the check book it was easier
  • Oh man! I'm the same way on all of this!!! its because I have CDO. That's OCD with the letters in the right order.
  • When it's full, it's full.
  •'s called OCD!!
  • When I'm at the pump, I go up to the nearest quarter. 25, 50, 75 and 00. It doesn't feel right if I can't do this.
  • Several days ago, my car had less than 1/4 tank of fuel. All I could do was $20, that filled up the! Also, yes you two are crazy. :)
  • I have a credit card I use for nothing but fuel I round off to double zero but if I hit ,01 I go to ,99 next time
  • I like to pump gas to the nearest dollar, but I take my time and top off the tank. My rule is DO NOT SPILL ONE DROP OF THAT BLACK GOLD. 
  • I usta count my change in the ashtray to use all my pennies when @ the pump otherwise they would pile up & not get used

However, there were also listeners who insisted this practice is bad for your vehicle:

  • You have to watch when you filling your car up your gas tank has a vent line to a carbon filter if gas gets in there you get a check engine light
  • You're not supposed to pump gas after the gas system auto stops. In time gas gets into a sensor and it will ruin it and give you worse is gas mileage. Will draw and evaporation check engine light
  • I used to try to end with a rounded up number at the gas pump until I learned that over filling your tank can damage your car.
  • Some manufactures like Honda does not recommend topping off tank. May cause check engine light to come on.

So, I did some research.  I started with my vehicle's owners' manual.  It did say not to overfill the tank, but not for the reasons people had shared.

"WARNING: Do not overfill the fuel tank. The pressure in an overfilled tank may cause leakage and lead to fuel spray and fire," the manual advised.

It also had this, "WARNING: Stop refueling when the fuel pump nozzle automatically shuts off for the first time. Failure to follow this will fill the expansion space
in the fuel tank and could lead to fuel overflowing."

Well, it didn't say I was damaging my vehicle; but it warned me I could start a fire or spill fuel.

I then checked out articles I could find online.

There are some that say topping off your tank can damage your car's vapor collection system.  None of them I found cited any manufacturers or research but did check with local mechanics who said things like overfilling the gas tank can force liquid gas into the charcoal canister or carbon filter in a vehicle and impact a car's performance or damage to the engine.  Another said that every time you put gasoline into the canister designed to capture vapor, it reduced the life of the part and could force you to have to replace it sooner.

Others made it a financial issue, explaining that the extra gas we force into the tank actually never gets into our vehicle's fuel system.  Articles claimed that the EPA mandates gas stations have a system to prevent spills and vapor releases that actually sucks the extra gasoline back into the pump and the station's tanks.  That would mean we are paying for gas we don't actually get.

All of that being said, I just feel better rounding the total.  I have never had to replace a charcoal canister or carbon filter in any of the vehicles I have driven while topping off my tank for decades.  Maybe I am paying for gas I don't actually get... but for a few cents and a feeling of satisfaction by having my total at a round number, that is a price I am very happy to pay.

It is kinda silly, no doubt, but we do lots of things in life that are kinda silly.

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