Filling gas tank is a problem

**EdPDX** · 09-12-2009, 02:29 PM

I have a 73 C20 that I have used since it was new. It is a great daily driver that has taken me across the US and back. Since the early eighties it has developed a problem at the filling station. 9 out of 10 times the tank will only fill to the half way mark on the gauge then abruptly shut off at the nozzle, spilling gas all over the place. I live in Oregon so I can't baby the nozzle to get it full. Every now and then I get the nozzle when the attendant is busy and I can get a full tank.

I know from what countless attendants have told me that this is very common for these older Chevys. Anyone know what the problem and fix is?

**KidHauler** · 09-13-2009, 09:45 PM

I baby the Mustang, too. You still get full service?!
I think it has something to do with the tank/filler neck design. They're bigger for the old "Leaded" nozzles, and I figure there's a back pressure valve in the new nozzles that isn't set up for the blow-by.
Those are just my thoughts, sorry, no fixes. How about cutting a section of radiator hose to set in the filler neck to see if that fools the nozzel?

Good luck,

**unplugged** · 09-13-2009, 11:55 PM

Sounds like a bad fuel level sender. Try recording the number of miles instead of watching the gauge. With a 30 gallon tank you should go 300 miles between fill ups. So next time you fill the tank. Write down the miles on the odometer and then check it when you stop to fill up again.

The sender is in the tank. You will have to drop the tank to replace it.

Around $70 and it looks like this.

**tbplus10** · 09-14-2009, 08:18 PM

That was a common problem on 70's GM trucks. I think GM had a TSB (or what passed for a TSB back in the 70's) to fix the problem, it had something to do with the charcoal cannister and evap system.
On my Dads 74 Chevy we used a section of radiator hose between the tank and filler valve. And if I remember correctly the only place we had trouble getting the tanks full was in Oregon where only attendants can refuel vehicles and they refused to use our adaptor.
Some motorcycle shops sell what they call a "motorcycle tank filler" it's a nylon tube that goes between the tank and the hose to stop a similiar problem with motorcycly tanks.