Flow of Diagnosis
Exhaust Leakage or Noise1. Verify the customer's concern by operating the engine to duplicate the condition.
2. Inspect to determine if any of the following mechanical concerns apply:
- External leaks in the exhaust system are often accompanied by noises and exhaust fumes. A visual inspection of the exhaust system usually will show the location of a leak. When checking for exhaust leakage or noise, inspect the entire system for burnout holes, loose or corroded clamps, muffler or exhaust inlet pipe. Examine the underbody for grayish-white or black exhaust soot which would indicate exhaust leakage at that point. On small leaks, have an assistant hold rags over the tail pipe outlet while listening for the leak. This helps magnify the leak.
- NOTE: In the event of a three-way catalytic converter failure, always check the muffler to be sure converter debris has not entered muffler. When testing for a rattle or vibration condition, it is helpful to use a rubber mallet. Tap on the exhaust components to simulate the bouncing action of the exhaust while watching for exhaust-to-body / chassis contact. Also look for loose or rusted flange connections, loose or damaged exhaust shields or clamps, and loose or broken exhaust outlet pipe frame brackets.
- Lightly tap on the muffler and three way catalytic converter to determine if there are loose or broken baffles in the muffler or a loose or broken element in the three way catalytic converter.
3. If the concern(s) remain after the inspection, determine the symptoms and go to the Symptom Chart. Symptom Related Diagnostic Procedures