Important information for service professionals
Excessive exhaust system noise is not only annoying for the customer, but can also be a symptom of a bigger problem. When troubleshooting an exhaust system noise complaint, keep the following in mind to successfully resolve the problem.
- When receiving a noise complaint, obtain the exact model, make, year and engine information. Ensure the application matches the catalog listing - year, make, model, engine - and that all pertinent footnotes have been considered. Do not accept "broad" application information in the catalog listing header.
- Reference catalog listing or bulletins to see if any of the parts have been superseded. In the catalog, these are noted with an "or" listing; the alternative part may have better acoustical performance. Also, ensure that part numbers have not been transposed.
- If possible, a record of exhaust system complaints and solutions should be maintained to determine if the problem is really with the part or rather if the specific vehicle or installation procedure could be at fault.
- Using caution (parts will get hot), move the exhaust system from side to side, and up and down to determine if the system is hung securely and not contacting the undercarriage of the vehicle.
- Start the engine in an open area and allow it to warm up. Once the engine reaches operating temperature, listen to the exhaust tone at different RPMs and loads to determine when the undesirable tone is most noticeable.
- If the noise is a popping sound at the tail pipe end, check under the hood and determine if the engine is equipped with an Air Injection Reaction (A.I.R.) pump. If an A.I.R. pump is present, disconnect the belt from the pump. If the noise ceases, the valve in the pump is faulty and should be replaced. If the vehicle is not equipped with an A.I.R. pump, the problem could be in the engine.
- Should further investigation be required, place the vehicle on a lift, raise the vehicle and inspect the exhaust installation. Check for the following:
- Contact with undercarriage
- Broken hangers and insulators
- Loose/leaking joints
- Muffler and resonator installed backwards
- Missing converter
- Resonator substitute pipe in use
- Worn out heat riser
- Engine with faulty timing
- Use of an "economy" or performance muffler
- Alterations to the original installation
The content contained in this article is for informational purposes only and should not be used in lieu of seeking professional advice from a certified technician or mechanic. We encourage you to consult with a certified technician or mechanic if you have specific questions or concerns relating to any of the topics covered herein. Under no circumstances will we be liable for any loss or damage caused by your reliance on any content.