Exhaust system, checking for proper seal

WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2004 Audi A6, 2003 Audi S6, 2003 Audi A6, 2002 Audi S6, and 2002 Audi A6. However, it is still accessible from the selected car via links, so may be relevant.

Start engine and let run at idle.
Seal tailpipes with cloths or plug for the duration of the leak test.
Check for leaks by listening at connection areas of cylinder head/exhaust manifold, exhaust manifold/front exhaust pipe etc.
Repair detected leaks.