740GLE - Fuel Tank Overflows during fillups

[petershen1984]

My 740 GLE fuel tank seems to overfill everytime after the automatic shutoff during fueling, leaving a small but risky puddle of fuel just behind my tire. I do not practice topping off the fuel after the shutoff--but sometimes I have to specifically tell the novice attendants not to.

Is there a seal, or an O-ring somewhere that needs to be replaced? Or could it be some kinda air pressure effect? I'm quite concerned with this safety issue.

I was wondering if the passage into the fuel tank is similar to that of the windshield washer tank?

[Volvord]

The 700 series fuel filler connects to the top of the fuel tank along with a breather line, fuel supply line, and fuel return line. This collection of lines enter the tank through a common plate that is held in place by a large threaded collar. Any of these lines could be loose, cracked, or the rubber gasket under the collar could be leaking. To access the hoses remove the tin access cover located in the trunk (on a sedan) or immediatly behind the left rear seat and under the carpet (on a wagon).

With the cover off the leak should be easy to locate.

[LaRy]

Don't worry, I would say that this is normal, at least if the car is made for filling leaded fuel. When I use the automatic shut down, I always reduce the filling capacity to "half" when getting closer to full tank. Otherwise it is doing the same as yours. In my case I have a 740 made for leaded fuel, the opening is approximately 50 mm wide, same as the tube down to the tank. I don't know if the same thing is happening with the smaller hole used when the car is made for unleaded fule.

[petershen1984]

My car is an 1988 model running on Premium Unleaded (98)- 10:1 compression, I can't go wrong, right? In fact I almost immediately start hearing engine knock if I downgrade to the next lowest octane..(95)

Thanks for the info, guys, I guess I'll just slow down even before the shutoff.