Exhaust system — leak test (Audi A6 C5)

In vehicles with a regulated catalytic converter, leaks in the exhaust system in the area before the oxygen sensor can cause the following malfunctions:

• a) difficulty starting the engine, the engine stalls;
• b) engine shaking at idle;
• c) the engine jerks when accelerating.

Checking for leaks

1. Start the engine and, while the engine is running, plug the exhaust pipe with a rag or a suitable plug.

2. Check the operation of the exhaust system by ear. If necessary, apply a spray used to detect leaks to the joints of the cylinder head and the exhaust manifold, as well as the exhaust manifold and the downpipe. Make sure that no air bubbles form in the specified areas.

3. Eliminate any leaks found.