Is filling up the gas to the rim a good thing or bad thing?

 

the only problem I could see was damaging your vacuum sensor. I can't see a benefit though. What additional benefit is there to having an extra .25 gallons?

 

^ I agree with this.

 

A gas pump is designed with a vapor recovery system. When it clicks off you are at that level. If you keep trying to put more in you are actually putting gas back into the gas stations tank and paying for it.

Heres an article explaining it
While you may be tempted to add a little more gas to your car to round off your dollar sale- even at the risk of overfilling the tank-this is one instance when you shouldn't go with the flow.
Topping off the gas tank isn't just bad for the environment, according to the U.S. Environmental Protection Agency (EPA), it's also detrimental for your wallet. Because the gas nozzle automatically clicks off when your tank is full, topping off can result in your paying for gasoline that is fed back into the station's tanks via the pump's vapor-recovery system, which prevents gas vapors from escaping into the air and contributing to air pollution. In fact, topping off might even foul up the mechanism and cause not only a gas-pump failure, but also a potential air-pollution problem.
Plus, evaporation from the spillage of gas from overfilling-which you've paid for, by the way-contributes to bad-ozone days, is harmful to breathe, and is a source of toxic pollutants such as benzene.
You also need some wriggle room in your gas tank to allow the gasoline to expand, otherwise the additional gas could evaporate into your car's vapor-collection system and damage it, leading to a vehicle that runs poorly and has high gas emissions. EPA

 

keraxis is 100% correct, my uncle runs a gas station he said the same thing. When you "top off your tank" you are actually paying for gas that is just recycling in the hose. The best way to get the most bang for your buck is to do as follows:

1. Fill gas until it automatically stops.
2. Manually push in/down the lever with your hand to tell the pump that you are finished. (I usually use a paper towel so my hands don't get all nasty)
3. Squeeze the trigger several more times until the gas empties out of the hose.
4. ???????
5. Profit / Get b!tches

 

manual says not to, what more do you want?

 

For all the cars that I owned, I always filled the tank all the way up to the rim. I am monitoring my gas mileage carefully and therefore I need to ensure that I fill up the tank to the exact same level every time. Result? I never ever had any problems.

Different cars are different. My G37 allows for 2 additional litres once the pump stops automatically. I remember that my old 2000 Protégé allowed 8-10 litres additionally. And my even older 1986 Dodge Charger had room for 10-12 litres after the the pump clicked. The variations are due to the shape of the tank intake pipe which, if not straight, can drain slowly into the tank and hence trick the pump shutoff mechanism too early.

 

If you just reset the trip odometer after every fill up and record the next fill up's volume, then you can accurately calculate gas mileage without having to top off.

 

The only problem I have with the vacuum stop on the pump is that the can prematurely cut off sometimes. I have a 94 civic I use for a commuter and that thing will click off almost 1-3 gallons before it actually needs to. Its an 8 gallon tank and I have had it cut off on me around 6 and change. What the problem is, is not the vapor its air pushing out of the neck of the fuel filler. So if you know your car then its no big deal, do what you feel comfortable with. But if you are unsure go with what the experts say.