Overfilling (Gas Topping) the 370z
 

Are you one of those guys that like to overfill your tank? I sometimes fill it up and put an extra half gallon in there. Am I harming anything? I know some people here that top it all the way full. Just wondering if it's a myth or what.

I tried searching inside the forum and couldn't find a thread about this specifically.

I don't think it harms in any way just spilled gas and a couple of wasted cents?


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I think the biggest reason not to overfill is that gasoline needs room to expand. If you overfill, I suppose you could mess up the EVAP system by getting liquid gas in to it, instead of gas vapors. At least, that's what I've been told by several mechanics. I just stop filling my tank at the first click.

Do not do it, it will mess up the EVAP and will not pass inspection.
Will cost a lots of $$$ to replace.

I overfill every car every time

I fill all the tanks to the brim on all of my cars for about a decade now. After normally filling a tank to the first click or normal container filling, I use a smaller 2-gal container (never through fuel pump nozzle unless the nozzle could go very slowly) to slowly and intermittently pour fuel in until the surface on the filler opening won't sink anymore; it's a very slow process and spilling must be kept to zero to minimum (usually a minor amount from splashing). For the hibernating cars, I may come back days or weeks later to top it off. I never had any problem with fuel vapor recovery system in any cars that I have owned or currently own.

Half a gallon is nothing. The additional amount that's "force-filled" varies from 2-4 gallons depending on the vehicle fuel tank, orientation of the vehicle while being filled, whether the vehicle is rocked, the amount of available fuel on hand, and lastly my patience.

I always overfill a little. If not the last LED on my gas meter wont light up.

It's the shoes man, I don't overfill cause I don't want gas on the bottom of my GODDAM SHOES!!!

:driving:

Why would you ever need to do this? I just recently filled up with 18.8 US gallons in the Z with no top off. Considering the capacity of the fuel tank is 19.1 US gallons, another 1/2 gallon would have overflowed :eekdance:

I know some people when they go to trips they put an extra gallon and a half in the tank. This will give them about an extra 40 miles of distance.

I always put 0.5 more gallons in the tank. Always have, no idea why.

Since I pay by credit card I don't anymore. Use to just to round it up to the next dollar.

I've always filled my car up as much as I can, usual until I can see gas at the top, never had a problem, with close to 600 tanks of gas on my Z alone.

With the fuel starvation issue of the Z, it makes no sense to me to squeeze in an extra half-gallon just to turn around and fill it before it gets down to a quarter-tank. I have just resigned myself to stopping at a gas station more frequently.

It really isn't a big time-waster--especially compared to any problems that over-filling or running too low might cause.