I have a 2000 Volvo V 70XC. On 6 occasions in the last month, my fuel tank, could not be filled at a gas station. Fuel ether ejects from the opening or more often the gas pump shuts as if the tanks is full. My car has 48,500 miles and this has only been a problem during the last month. The behavior appears to car rather than gas pump dependent. It occurs with all nozzel types (that I encounter in Pennsylvania) - long nozzels, short nozzels and with and without rubber vapor closures associated with the nozzels. When ever the fill malfuncion occurs it is independent of the rate at which I fill the tank.

This behavior is erratic and occurs perhaps half the time. It can occur when the car is hot or cold, tank is nearly full or empty, e.t.c.

I have had the car worked on by a Volvo master technican with a good reputation. He can find no problem with the car evidenced by computer diagnostics, e.t.c.

This is clearly a car dependent problem and independent of gas pump nozzel type, filling rate, e.t.c. The car warranty exprires in 1500 miles.

Has any one seen such behavior with Volvo XC's or V70's? Can anyone suggest any repairs under than my demanding the dealer start replacing all fuel tank and related system components as a warranty item? A car is not of much use if one cannot rely on it refueling functions.

There's a flap door type device inside the gas tank and THAT's what's stopping the fuel when you're trying to re-fuel.
The cure is another gas tank but with a XC, it's no easy thing and no one would want to replace that unless forced. The whole rear diff/axle assembly must be lowered to do it and it's a bummer.
On a 2WD Volvo, it's a piece of cake in comparison.

I had this identical problem with my 1998 S70, even when new (no need to wait 40K miles). A Dealer tried three different times to duplicate and diagnose the problem, but could not. Each time he filled the tank at no charge, so I didn't really mind. Plus I had a "work around". An experienced attendant said this was a common Volvo and Mercedes problem and suggested I hold the filler hose slightly back from the "fully bottomed" position, air could escape and the filling proceeded normally. It takes a steady hand but works perfectly. My permanent fix was to make a spacer from a white plastic pipe fitting (40 cents at Home Depot) with numerous holes drilled in the sides for air to escape. I stored the spacer in a self-seal food bag.

It sounds as if the air in the gas tank can't escape at the rate it is being displaced by the fuel you are adding. Could be the 2 small vent holes at the top of the refill shaft (where you put the nozzle in), or it could be the venting tube which, I believe, feeds into a charcoal (or some other type filter) canister. Could be that the vapor filter in this canister is ready to be replaced, or the tube which feeds into the canister is pinched/blocked.
Good luck.

If you look under the r/r corner where the fuel filler is, there is a black plasic cylander with nothing attached to the bottom, but a 1/2" or so hose atteched at the top end. Thsi is the fule tank vent filter, it allows air to escape, but keeps crap from getting sucked in or crawling in. Spiders like the smell of gasoline, and they build nests and lay eggs in the open end of that filter. You can take a pen or something and clean it out. If that doesn't help, then it needs to be replaced. Where I work, we've replaced a couple of them under warranty.

It's not a "fuel tank vent" as by todays emissions standards, that's illegal.
What that really is is part of the carbon canister evap system and it's the INTAKE for air entering the carbon canister. It has nothing to do with why anyone would have problems refueling but you're right about spider nests in there causing problems. When it's clogged with a spider nest, it'll set a check engine light with codes but the car won't have any driveability, refueling or other problems.