Hello,
I own an Audi A6 3.0T Quattro Prestige, purchased from original owner in Jan 2018, when car had 61k miles on it.
In March, Audi dealer performed work under 20AR recall for fuel line leak. At that time, the odometer showed ~ 65k miles.
Between March and present day (Mid-Oct), another 20k miles have been driven.

Unrelated to the recall work, the vehicle suffered a drive belt failure, apparently due to a problem with the crankshaft pulley harmonic balancer which reportedly loosened the belts and caused one belt to fail, which in turn shredded another beltThis repair was relatively invasive and upon return of the vehicle, several examples of sloppy work including screws on one or more assemblies not properly tightened, an uncoupled air intake duct at the top of the engine as well as a disconnected pressurized air breather vent hose under the air intake resonator.

The air intake issues were immediately discovered (belching smoke and significant engine vibration) and corrected by simply reattaching the hose and recoupling the duct.

Within a day after delivery of the vehicle after the drive belt repair was complete, it exhibited symptoms of a fuel leak - I.e. small puddling of fuel under the vehicle near the rear driver side tire and distinct fuel smells during and after the engine was running. At that time, the amount of fuel in the tank was approximately 30% of capacity.

The car was returned to the Audi dealer service facility, but just prior to that, the fuel tank was refilled to the top.
When the car was driven into the shop and then hoisted up to look underneath, the vehicle was “raining” down gasoline. It appeared that the gas was coming from somewhere around the tank itself as the leak was directly under the tank and near the point where the exhaust line splits into two pipes.
(See attached video clip)
Given the obstructions in the way, it was not possible to see the exact source of the leak, but despite this, the mechanic claims the fuel tank has failed (most likely at the seam) and needs to be replaced - a significant multi-thousand dollar undertaking on a vechicke no longer under warranty.

By writing to those on this forum, including this level of detail, I’m hoping to solicit feedback and advice as to next steps.

My own personal belief is that the leak is associated with the fuel line, not the tank. Why?
- a fuel tank that is only 30% full won’t leak gas from the seam
- a fuel tank seam failure would seem more likely to degrade over time, not fail in a catastrophic, instaneous event (no prior evidence of fuel leak during 25k miles driven - until after drive belt work completed.)
- leak seems to subside when engine is off - even when the tank is full - but starts “raining” again as soon the engine is started and presumably the fuel line is under highest levels of pressure.

Has anyone else experienced this situation?
Does my logic hold up scrutiny from those who are familiar with the issues described?

Id would be most grateful for any and all feedback - either in support of my hypothesis or to poke holes (no pun intended) and refute it,

The same Audi dealer did the drive belt repair.
Twice, actually.... the first time they didn’t take the time to investigate what had caused the drive belts to shred.
Instead, they just replaced the belts and then took it for its test ride after repair. No more than a mile down the road into the test ride and the belt shreds again! This time, I guess someone suggested they look into the root cause a bit more thoroughly - and they found the crank shaft pulley / harmonic balancer anomaly.