Have you tried this? Rather than pushing the pipe all the way in, leave it out and inch or two and let the handle sag down. This way, the pressure should be able to vent through the small gap between the filler hole and the pipe. I think the problem you’re experiencing is related to the environmentally-driven new gas pump technology (that, in an effort to avoid spilling even a drop of gas) cuts off at even a hint of pressure. It doesn’t sound like there’s anything wrong with your car.

The gas leaking out under the car is what is supposed to happen if the tank is over filled. It will leak out until it goes down to the maximum level the tank can hold.

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Michael

1988 300 SL (5 Speed)
1994 E320 Wagon
1997 C230