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Overfilling gas

relive

Ready to race!
Location
USA
How much would I need to overfill the gas tank before it becomes a problem for the charcoal canister?

I never fill more after the first click, but today, the pump was faulty and kept clicking off early, so I had to manually pump. I turned on the ignition to monitor the fuel gauge. Based on the MPG reading on the car (and accounting for the fact that it reads about 6% too high), I calculated that I needed to pump 7.8 gallons for a full tank. The fuel gauge read full a bit after 7 gallons (don't know exactly when because I was running back and forth), but I kept pumping and ended up at 7.9 gallons. I felt more resistance from the handle for the last half gallon, and I think I smelled vapor at the very last second before stopping.

Did I overfill, and if so, what kind of symptoms should I look out for if there is a potential issue?
 

kevinkar

Drag Racing Champion
Location
United States
If you're a normal person you've overfilled one of your cars at least once in your lifetime and I'm pretty sure the car was OK. They don't design in a single point of failure in cars like at the fill tube. Sure, you don't want to fill to the cap and you don't want to keep doing it but the car won't die because of it. Just ignore it and try to be more careful in the future.
 

bcgti

Ready to race!
Location
BC
My MK6 lasted about a year of ‘topping off’ before I had to replace the check valve. I replaced it myself and learned my lesson! Got an evap error code that would come and go but other than that it drove just fine (before fixing it).

So I believe it would take a lot for it to become an issue.
 
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Strange Mud

Autocross Champion
Location
Small Town CT
Car(s)
Assorted
occasionally I doubt there is real damage....w/o insulting unless you have a real good reason (last gas for 481 miles ;)) if you know you need about 7 gallons stop at 6.

Mud
 
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imthanick_a

Autocross Champion
Location
Ohio
Once or twice won't hurt it, just don't make it a habit. I don't see any reason to try and squeeze out an extra 15 miles from your tank and risk doing damage to the car. Just fill it up til it stops (unless its obvious that its not full because the pump isnt working correctly, that has happened to me a few times)
 

imthanick_a

Autocross Champion
Location
Ohio
I've always topped up every car and been lucky to not have issues. I didn't even realize it was an issue. I guess I'll stop.
Most of the time its no problem. Except when it is.

Tons of people fill up every time with no problems, but its not a good habit to get into. Those evap systems are pricy to fix. Also, the extra gas you pump just cycles back into the nozzle to prevent overflow so you're just wasting money at that point. Paying the gas station to pump their own gas back into their own storage tanks
 

GTIfan99

Autocross Champion
Location
FL
Most of the time its no problem. Except when it is.

Tons of people fill up every time with no problems, but its not a good habit to get into. Those evap systems are pricy to fix. Also, the extra gas you pump just cycles back into the nozzle to prevent overflow so you're just wasting money at that point. Paying the gas station to pump their own gas back into their own storage tanks

I was stimulating the economy. Lol.
 

relive

Ready to race!
Location
USA
Just fill it up til it stops (unless its obvious that its not full because the pump isnt working correctly, that has happened to me a few times)

That's exactly what happened. The pump wasn't working and I tried to calculate what the first click "would" have been.

Thanks everyone, I appreciate your input!

I'm not overly worried; just wanted to know what to look out for and I will definitely underfill in the future when the pump malfunctions.
 
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imthanick_a

Autocross Champion
Location
Ohio
That's exactly what happened. The pump wasn't working and I tried to calculate what the first click "would" have been.

Thanks everyone, I appreciate your input!

I'm not overly worried; just wanted to know what to look out for and I will definitely underfill in the future when the pump malfunctions.
If you smell gas in the cabin after you fill up, thats how you know the charcoal canister became saturated. It usually dissipates after a few minutes of driving though. I had that smell before I got the recall work done for replacing the charcoal canister
 

relive

Ready to race!
Location
USA
If you smell gas in the cabin after you fill up, thats how you know the charcoal canister became saturated. It usually dissipates after a few minutes of driving though. I had that smell before I got the recall work done for replacing the charcoal canister

I didn't smell anything in the cabin at all. I think I smelled vapor right before I stopped the pump, so I thought the tube might have overflowed, but there was nothing when I removed the pump.

Sounds like everything's fine. I will scan for codes in the next few weeks and will be more careful in the future. Thanks again!
 
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