SUBJECT: Excessive Exhaust Noise/ Vibration During/After Underbody Contact With Moisture
NO: 11-04-96
GROUP: Exhaust
DATE: June 21, 1996
MODELS: 1995 - 1996 (PL) Neon
SYMPTOM/CONDITION:
Excessive exhaust noise and/or vehicle vibration during/after vehicle is driven through puddles or underbody contact with snow/slush. The intermediate pipe may be contacting the tunnel heat shield when it is cooled from the water/snow contact.
CAUTION: TO PREVENT SERIOUS INJURY FROM HOT EXHAUST COMPONENTS, INSURE THAT THE VEHICLE HAS NOT BEEN DRIVEN AND THE EXHAUST IS COLD BEFORE INSPECTION AND REPAIR.
DIAGNOSIS:
With the vehicle on a suitable hoist, inspect the tunnel heat shield for any marks where the intermediate pipe has made contact. If the pipe or heat shield show signs of contact, or the pipe appears to be out of alignment with the tunnel, proceed to the repair procedure.
PARTS REQUIRED: AR 4495951 Isolator, Exhaust Rubber
REPAIR PROCEDURE:
This bulletin involves aligning the exhaust pipe in the tunnel and straightening the tunnel heat shield.

1. Measure the clearance between the intermediate(AI@)pipe and shield/floor pan in the areas of contact. Record this data on the repair order for future use.

2. Inspect the catalyst assembly to insure that the alignment button is fitted into the notch on the AI@ pipe.  See Figure 1.

3. If the alignment button is fitted into the notch and the AI@ pipe is not in the center of the tunnel, remove the alignment button to allow centering of the AI@ pipe in the tunnel by the following procedure:

  • Separate the AI@ pipe from the portion of the pipe with the alignment button.
  • Using a grinder or chisel, remove the alignment button to allow the pipe to turn easily within the AI@ pipe.

4. Inspect the rubber isolators on the AI@ pipe and muffler for side to side movement, by pushing on the pipe. The rubber isolators are designed for forward and rearward movement only. If the exhaust system cannot be centered as described in steps 2 and 3, replace the rubber isolator with P/N 4495951.

5. If the AI@ pipe is correctly aligned down the center of the tunnel and still contacts the heat shield, the heat shield should be bent slightly to align. Measure between the AI@ pipe and the heat shield in the areas showing contact marks, there should be a minimum clearance of 25mm. See Figure 2.

In the areas that are out of specification, use a pair of pliers to bend the heat shield to provide the proper clearance. Figure 3.

Measure between the heat shield and the floor pan in the areas showing contact marks, there should be a minimum of 5mm clearance. Figure 3.

In the areas that are out of specification, use a pair of pliers to bend the heat shield to provide the proper clearance.

CAUTION: DO NOT MOVE THE HEAT SHIELD TO THE EXTENT THAT IT CONTACTS THE BODY OR BECOMES LOOSE.

6. Test drive the vehicle and listen for the noise/vibration, If the noise is still apparent, further adjustment of the heat shield will be needed, repeat step 5 and increase the clearance.
POLICY: Reimbursable within the provisions of the warranty.