Radio - Excessive AM Static Noise with Engine Running
FILE IN SECTION: 9 - AccessoriesBULLETIN NO.: 53-96-02
DATE: June, 1995
SUBJECT:
Excessive AM Radio Static Noise with Engine Running (Ground Exhaust System to Vehicle Underbody)
MODELS:
1994-95 Buick LeSabre, Park Avenue
1995 Buick Riviera
1994-95 Cadillac Concours, DeVille, Eldorado, Seville
1994-95 Oldsmobile Eighty Eight, Ninety Eight
1995 Oldsmobile Aurora
1994-95 Pontiac Bonneville
CONDITION
Some owners may comment on excessive static noise noted while listening to AM radio stations with the engine running. Noise dissipates when the engine is turned off.
CAUSE
Ignition noise is transmitted from the engine to the exhaust system. Because NVH concerns have resulted in the exhaust system being suspended by rubber lined hangers, the system is not grounded. The exhaust system acts as an antenna and rebroadcasts the ignition noise, having the greatest impact on AM band reception.
CORRECTION
Ground the exhaust system to the vehicle underbody using the following procedure:
Materials needed:
1. One 1/4 - 3/8 inch wide braided ground strap with a crimp-on ring terminal on at least one end.
2. One # 10 or larger sheet metal screw.
3. One stainless steel hose clamp with a diameter to match the exhaust system being modified.
Important:
Clean attachment area before securing hose clamp to ensure a good ground connection.
Install or Connect
1. Hose clamp (Figure 1, Item 1) around exhaust system just rearward of the catalytic converter.
2. Bare end of ground strap (Figure 1, Item 4) between hose clamp and exhaust. Fully tighten clamp.
3. Ground strap ring terminal (Figure 1, Item 3) to underbody using sheet metal screw. Locate an unused floorpan hold or drill pilot hole in nearby heat shield to match screw size (Figure 1, Item 2). Keep hole as close to the hose clamp as possible. Make sure ground strap is not stretched tight and allows for normal exhaust system movement.
WARRANTY INFORMATION
For vehicles repaired under warranty, use:
Labor Operation Labor Time
N6478 0.3 hr