Good To The Last Drop... Or Is It?

top off the gas tankI don't like the word hate, but there are just a few things I despise in life.   Traffic, 7 am morning meetings, mosquitoes, etc.  The thing I despise when it comes to my car is pumping gas.  What a nuisance to stop in the middle of my plans of getting home or getting to work or getting somewhere, so I can pump gas.  *Side note* See my previous blog on running your tank to E and the damage it does to your car.For that reason, I try to make the least amount of trips to the gas station as possible... or I make a trip to New Jersey where every station is full-serve; the best part about Jersey.  When I finally get to the gas station I make sure I squeeze every last drop of gas out of the pump or the technical term, topping off the gas tank. When the pump shut off automatically, I would press the handle on the nozzle  until it automatically clicked off again.  Then, I would repeat that one more time.  I was trying to get as much gas in the tank as I could.  I thought it was saving me time between trips.  Plus, with gas prices constantly rising who knows when it will be this cheap again.My auto airhead beliefs have been steering me wrong again!I know it looks really pretty when $30.00 shows up on the pump instead of $29.53 or like me, you are trying to get as much gas in the tank as possible, but you could be causing damage to other parts of your car and polluting the environment.  The pump is designed to turn off when the fuel reaches a certain level in the tank, leaving room needed for the emissions and fuel system to operate correctly.  Do not top off the gas tank when you are filling up! Here are three examples why:

  1. There is gas AND gas vapors inside your gas tank.  Gas expands, especially when it is hot out.  As the gas expands it needs to go somewhere.  The gas rises and the vapors are forced out of the tank and into the emission system of your car.  Parts of the emission system collect and store gas vapors to be burned in the engine later.  If you top off and there is too much gas in the tank, as it expands liquid gas is forced in to the emission system which is only designed for gas vapors.  This can cause your check engine light to come on, your car to run poorly, and/or you pollute the air more with your exhaust .  You will need to replace any damaged parts of the emissions system.  Specifically something called the charcoal canister.
  2. A lot of gas pumps are designed to feed gas into their pumps to prevent vapors from escaping into the air and contributing to air pollution. Any additional gas you try to pump into your tank may be drawn into the vapor line and fed back into the pump.  Causing you to pay for gas that was returned to the station.
  3. Any time you top off you created a great possibility of gas spilling on the ground and vapor releasing into the air.  Very bad for the environment.

Moral of the story, top off my coffee, not my gas tank!

Related Links
Running Your Gas Tank on Empty Is Not Living On The Edge
Don’t Ignore Your Leaky Car Part 1
If You Think Of An Engine Like A Vagina…

 

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