I usually agree with most of what you guys say. But, in a recent article, you stated that you shouldn’t do this. If you live across the street from the gas station, maybe, but most of us have a distance to drive before we get home. And, there is probably a 99% chance that there is a trapped air bubble in the tank and when you move, that will leave more room in the tank too. In my case, I have a 15 mile drive to get home from the closest station and at 21 mpg, I’ll use about 3/4 of a gallon before I get there. Just want to keep you guys on your toes–keep up the good work.
I don’t care if there is an air bubble or how far you have to drive to get home. Topping off the tank will damage important components on many models. It isn’t worth it.
As I have said before, if I was about to set off on an excursion across the Gobi Desert, I would take the chance of topping off my tank, simply because of the incredible distances between gas stations in an environment like that.
However, the vast majority of Americans do not live far enough away from a gas station to make it a worthwhile trade-off to risk a $300.-$400. carbon canister replacement in order to be able to drive perhaps 10 or 15 miles further. All it takes is a little planning and watching your gas gauge in order to avoid running out of gas in most of these United States.
The issue isn’t how much gas is in the tank when you get home. It’s how much is in the tank as soon as you finish filling up. If it’s high enough to reach components that shouldn’t be reached, then damage could be done.
Don’t second guess the manufacturer or those who have your interest at heart. Stopping the hose at the first click saves you from expensively contaminating the vapor cannister. The difference between “topping it off” and doing the proper thing is less than a quart at most.
You you want to risk sever hundred dollars worth of damage in order to add a few miles to your cruising distance go ahead.