When I told him about people here discussing the topping off, he told me of An Ody that kept coming in for repairs BECAUSE of just topping off. The cars that would be sensitive to this would be newer than '98 or so. They'd be the ones with OBDII systems. That's when they added the vapor thing to them for the clearer air.
He's seen a few over the years. It may depend on how much extra you put in it....
An '89 didn't have anything extra in the neck of the filler tube. So you could top away without any problems. The ones with OBDII would also be adding to the pollution in the air to top them off, even if you didn't mess up the EVAP system.
Our old Chevy truck would spit at you if you went too far & so does out boat! It's nasty! Then you have to careful get the gas off the finish. It has done some damage to the striping in the back of our boat where the filler is! No matter how hard we try, it still spits!!
Oh drat! I'm supposed to feed him too!!??? Oh man, maybe that's why he's so thin!!!
