Exhaust System - Snapping/Pinging/Rattling Noises

NO.:
11-04-92

GROUP:
Exhaust

EFFECTIVE DATE:
Nov. 25, 1992



SUBJECT:
Pinging/Snapping From Exhaust System



MODELS:

1992 - 1993 (AY) Imperial/New Yorker Fifth Avenue


SYMPTOM/CONDITION:

Vehicle may exhibit one of the following conditions:

1. A loud pinging/snapping noise may be heard coming from under the middle of the vehicle after the engine is shut off. The noise may start immediately after shut off and last up to twenty minutes. The noise may also be heard during hard acceleration or heavy load.

2. A rattling noise may be heard from under the middle of vehicle during idle.


DIAGNOSIS:

Condition number one may exist on vehicles built from 11/13/91 through 12/2/92. Condition number two may exist on vehicles built from 1992 model year launch through 11/12/91.

NOTE:
MILD CRACKING/SIZZLING NOISE IS NORMAL FOR STAINLESS STEEL EXHAUST SYSTEMS DURING COOL DOWN.

Condition Number One

The vehicle must be fully warmed by driving a minimum of two miles, highway speed (55 mph +) is preferred. Idling is not always sufficient. Park the vehicle and shut off the engine. Listen for a loud pinging/snapping noise and verify it is coming from the exhaust extension/resonator assembly.

Condition Number Two

Start the engine and let idle in park with the parking brake set. Roll the driver's window down or exit the vehicle. Listen for a rattle coming from under the vehicle. If no rattle is heard, rev the engine to about 1500 RPM and return to idle, the rattle will be more noticeable when the exhaust system is cold than warm. The rattle may even go away after warm up.



PARTS REQUIRED:

1 Pipe Assembly, Exhaust Extension with Resonator 4427784

1 Clamp, Extension Pipe to Tailpipe 4495532


REPAIR PROCEDURE:

This bulletin involves replacement of the exhaust pipe extension with resonator assembly.

1. Verify the vehicle exhibits the pinging/snapping and/or rattle condition(s).

2. Replace the exhaust pipe extension with resonator assembly using the procedure in the appropriate service manual.


POLICY:
Reimbursable within the provisions of the warranty.


TIME ALLOWANCE:
Labor Operation No. 11-20-10-90..........0.6 Hrs.


FAILURE CODE:
P8 - New Part