Exhaust - Noises Driving Medium Grades/Accelerating
File In Section: 6 - EngineBulletin No.: 47-60-06D
Date: May, 1996
Subject:
Popping/Fluttering/Ticking/Spark Knock/Clunking Noise While Driving up Medium Grades or Accelerating from a Stop (Replace Exhaust Seal)
Models:
1995-96 Buick Park Avenue, Riviera
1996 Buick LeSabre, Regal
1995-96 Oldsmobile Eighty Eight, Ninety Eight
1995-96 Pontiac Bonneville
with 3800 Series II Engine (VIN K - RPO L36)
1996 Buick Park Avenue, Riviera
1996 Oldsmobile Eighty Eight LSS
1996 Pontiac Bonneville
with 3800 Supercharged Series II Engine (VIN 1 - RPO L67)
1996 Chevrolet Lumina
1996 Oldsmobile Cutlass Supreme
1996 Pontiac Grand Prix
with 3.4L Twin DOHC (VIN X - RPO LQ1)
This bulletin is being revised to correct the labor operation number. Please discard Corporate Bulletin Number 47-60-06C (Section 6 - Engine).
Condition
Some owners may describe a condition of a popping, fluttering, ticking, or spark knock type of noise while driving up medium grades or accelerating from a stop. Some owners may describe a clunking type noise that seems to originate from the rear of the vehicle.
Cause
The original seal may become momentarily seized to the front exhaust pipe flange. When this happens, normal engine movement may cause the flat side of the seal to move away from the exhaust manifold. When the seal moves away from the exhaust manifold flange, an audible exhaust noise may be heard. Also, a popping noise may be heard due to the seal snapping back in position and banging against the exhaust manifold flange.
Correction
To diagnose the condition, set the parking brake, start the engine and run until operating temperature is reached. Alternately place the gear selector in drive and reverse then lightly load the engine. Listen for noise around the exhaust seal area. The vehicle may need to be raised in the air to gain access for listening around the entire seal area.
If a noise is detected, replace the exhaust seal. The replacement seal is made from a material that is less susceptible to seizing to the front exhaust pipe flange as compared to the original seal. The replacement seal is also designed to fit snug around the exhaust manifold flange tube.
Important:
Insure the flat side of the exhaust seal is seated firmly against the exhaust manifold flange.
Parts Information
Description Part Number
Exhaust Seal 24506449
Parts are currently available from GMSPO.
Warranty Information
For vehicles repaired under warranty, use:
Labor
Operation Description Labor Time
Seal, Front Use published
L2090 Exhaust labor operation
time.