I have overfilled or "top off" my fuel tank

Hi guys, I just had a brand new Hyundai vehicle and it is a gasoline one, I had it since 3 days ago.

I made a mistake by not “quickly” reading the owner’s manual first specifically the first few pages concerning information about the gasoline to use and break-in instruction.

So from the dealer I went to straight to the gasoline station to put in some fuel and the very first mistake I did was to to “top off” the fuel tank. This is my first brand new gasoline vehicle and all of the vehicles I had are diesel engine vehicles. I just realized after reading and watching videos on Youtube that topping off is dangerous and will damage your “EVAP” system.

The amount of excess fuel I topped off was around 4-5 liters, the fuel tank capacity of my vehicle is 40 liters and I have topped it off at around 45 liters. Although I have not topped it off up to the brim.

After learning that we should not top off our fuel tanks, this will be the first (for gas) and last time that I will top-off the fuel tank.

Now, my question is, is the EVAP system of my brand new vehicle already compromised? Should I bring it to the service center and have the charcoal canister replaced?

Sounds like you filled it up 3 days ago… Have you not driven it for 3 days now?? Did the check engine light come on???

Just drive it and see what happens (probably nothing)…

Don’t worry about it. The car is fine.
Just don’t make a habit of topping it off.

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I think the dangers of filling to over flowing are a litttle exaggerated but not a good long term habit. I always stop at the first click and it becomes a habit. Just make sure you don’t put diesel in out of habit.


Your check-engine light will come on if there’s a problem with this system. If it doesn’t, then you got away with doing this.

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My understanding is newer cars have systems to prevent damage from over fueling. No CEL, you’re okay.
In the future, when the gas pump clicks off, you’re done, don’t add anymore.