Gas Pouring out of Tank when Opening the Cap

I have a 2001 Audi A4 2.8 Quattro. The check engine light goes on from time to time. Opening and closing the gas cap usually takes care of it. This time when I opened it after filling it up (did NOT overfill the tank) gas came pouring out. I let it pour out until it stopped. Cleaned it all up. Put the cap back and started it. Opened the cap again and gas came pouring out again. Called the dealer, they said I need a new tank (!) at a tune of almost $4000. The car is in like new condition. It has been babyed. Is this really the only remedy?

How full was the tank? If the tank is pressurizing, I’m betting the problem is with the evap system. The evap system should keep the empty space in the tank in a vacuum to prevent gas fumes from leaking to the atmosphere. The fumes are supposed to be sucked into the engine to be burned.

Stop going to the dealer, and find a good independant mechanic. Especially one that specializes in Audis and VWs.

This is an EVAP system fault. Perhaps a saturated canister and/or faulty purge valve.

There aren’t a lot of places here that specialize in Audi. I did call the one other place in town and he said he had never heard of this problem in his 35 years. The dealer has been pretty dead on in the past and they seem to be completely confident the whole tank needs to be replaced. I am taking the car into the other Audi guy on Monday. What all is the EVAP system?

Are these parts outside the tank that can be replaced or do I have to replace the whole tank to get to the canister and purge valve? Thanks for your input guys.

The parts are outside the tank, BUT, get the cel codes read first to ensure the correct area of the fault.

I’m not sure about your vehicle, but both of my GMs have the canister and purge valve under the hood. I would imagine yours are attached to or near the engine as well.

To see where they are located check a Haynes or Chilton repair manual specifically written for your vehicle. You can find these in just about any automotive supply store.