Do you fill your car all the way to the top or the first click? I read somewhere it's bad for the car to fill all the way to the top due to vapor collection.

__________________
If the car feels like it is on rails, you are probably driving too slow.

I always fill to the first click. I don't see a reason to fill beyond unless paying with cash and you want an exact amount. How much further will your car go with that little extra gas in the tank? Probably not much. And yes the vapors will expand as they are heated up. Thats why I always like to pump my own gas.

Yes, fill up to the first click. After that you are overfilling and with repeated overfilling you will damage emissions components.

__________________

'07 Porsche Cayman S: de-snorked... more mods to come. '05 Dodge Magnum RT: catback, high-flow cats, custom intake, projector headlights, SC FlashPaq... and on and on.
Blog: leanstartups.com

Just step on the gas when when you leave the gas station and you won't have to worry much about how much gas is in the tank

On some cars, and I don't know that the Cayman is one of them or not, topping off during filling can cause fuel to be drained into the activated charcoal canister that holds gasoline tank vapors when the engine isn't running. Normally these vapors are then sucked into the engine with vacuum when the engine is running. If the charcoal canister gets saturated it can cause starting and/or driveability problems.

In general topping off your tank is a really, really bad idea. Modern fuel systems are sealed, and as you pump in fuel the air must escape through a vent that terminates in the filler neck. Cover the vent with fuel and the excess gasoline you're pumping in might squirt back at you.

Topping off falls into my "just don't" category. Here's in Oregonia, one of the two stupid states where you can't pump your own gas, I have to remind every attendant I know not to top off the tank. They like to round your purchase to the nearest whatever. Dumb behavior.

I worked at a gas station for four years while in college. When you top off the tank the back pressure that builds up causes the hose at the pump to fill up with gas. So you are actually paying for gas for the next customer.

Thanks for all the great responses. One click for now on. Whew I never knew it would be that bad on our engines.

__________________
If the car feels like it is on rails, you are probably driving too slow.

Here is another factor to consider when buying gasoline. The cooefficient of expansion of gasoline is .000528 per degree farenheit. The gasoline stored in tanks below ground is somewhere between 55-60 degrees F (the government uses 60F). When gasoline is pumped into your car it depends on the temperature as to whether the gas will expand or contract. Remember that there is gasoline above the ground in the pump, hoses etc. That gasoline is at approximately what the air temperature is.

When the temperature of gasoline rises above 60 degrees, the gasoline expands but pumps don't account for the bigger volume and consumers receive less gasoline than they should. The technology to adjust for temperature has already been installed in Canada (since colder temperature gas costs the companies) but domestic oil companies have resisted because they made an extra $500 million in profits per year alone in California due to failure to adjust for gasoline temperature. Hawaii is the only state to adjust its pump calculations for hotter gas.

__________________
I’ll do anything for money except work. You have to draw the line somewhere.

You can't pump your own gas??????? What's the other state with this ridiculous law? Why would they do this?? Did some of the Oregonian lawmakers have a stroke?

New Jersey. They will actually get pissed (because they can be fined) if you pump your own gas.

__________________
Gator Bite
(View My Articles : Blogs : Car : Profile)

Although you can't pump your own gas (in NJ) it's still cheaper per gal. than in neighboring states where you can pump it yourself. Perhaps it was a stroke of genius!

BTW My hands never smell from gasoline when someone else pumps it.

I really don't mind not having to pump my own gas when I'm in NJ. Pumping gas isn't rocket science. You can tell the service station attendant when to stop if you don't want the tank topped off.

__________________
I’ll do anything for money except work. You have to draw the line somewhere.

just do the first click

Oregon is such a bizarre, contradictory place to own a car. There's no sales tax. It costs $30 per year to register your car. There are miles and miles of two-lane winding roads seemingly made for the Cayman. We have fewer state troopers than any other state in the union, I'm told (though the ones we do have set speed traps, and there's no law against it like there is in CA). On the other hand, the highest speed limit in this huge, unpopulated state is 65mph, the interstates are narrow and crowded, studded snow tires are legal (so the roads get dangerously grooved and torn up), and the damned fools won't let you pump your own gas. It's an Oregon tradition, and anytime us unwanted transplants from California bring up changing the law to allow self-serve gas we get slapped down like unruly puppies begging for table scraps.