Checking the tightness of the exhaust system (Mercedes-Benz C-Class W203)

In models with a petrol engine and a regulated catalytic converter, leaks in the exhaust system before the lambda probe can lead to the following malfunctions:

• Difficulty starting the engine.
• Engine vibrations at idle and engine stalls.
• Jerks when accelerating the car.

Test conditions: Engine cold or warm.

1. Start the engine and while the engine is running, cover the muffler with a rag.

2. Listen to the exhaust system to detect leaks. If necessary, spray the cylinder head/exhaust manifold and exhaust manifold/head pipe connections with a leak detection agent and look for any bubbles that may form.

3. Fix the leak.