Audio System - A/M Band Noise
BULLETIN NO.: 98-T-43AISSUE DATE: November, 1999
GROUP/SEQ. NO.: Electrical-06
CORPORATION NO.: 99-08-44-009
SUBJECT:
Audio System AM Band Radio Noise
(Install Engine-to-Chassis Ground Strap)
Due to revisions under Models Affected and Parts Requirements, this bulletin is being revised and supercedes bulletin 98-T-43, which should be discarded.
MODELS AFFECTED:
1995 - 1999 Saturn S-Series vehicles built up to and including VIN XZ319158 (1999 vehicles built after VIN XZ319158 had the ground strap installed during production.)
CONDITION:
Customers may comment that while listening to certain AM radio stations, they hear ignition related noise. The radio noise follows engine rpm.
CAUSE:
During normal engine operation, ignition components in the engine compartment emit certain electrical "noise." Depending on the location of the vehicle antenna mast, these electrical noises may enter the radio through the antenna system. These noises may then be interpreted by the radio as radio signals and be amplified in the form of noise. Typically, the only AM radio stations that are affected are "fringe" stations. (Fringe stations are stations that are beyond their intended usable range.)
IMPORTANT:
The range for most AM stations is greater than for FM stations, especially at night. The longer range, however, can cause stations to pick up noise from things like ignition components, storms, and power lines.
CORRECTION:
Attach ground strap from upper engine mount to right side strut attachment stud.
PROCEDURE:
1. With engine running, verify noise is on fringe AM stations only. (If noise is on AM and FM, just FM, and/or cassette/CD, refer to Audio System section of the appropriate model year Audio System & I/P Cluster service manual and/or Technical Bulletins 95-T-28A or 98-T-19.)
2. Using a jumper wire with alligator clips, attach one end to engine front cover torque axis mount stud and the other end to the strut tower nut (do not attach to stud; the nut is a better ground).
^ If noise is reduced or eliminated, continue with step 3.
^ If noise is not reduced or eliminated, refer to the Audio System section of the appropriate model year Audio System & I/P Cluster service manual for additional diagnostic information.
IMPORTANT:
When removing engine mount-to-front cover nut, use a 7 mm wrench on top of stud to prevent stud from rotating.
3. Remove engine mount-to-front cover nut from rear stud.
^ If stud rotates while removing nut, go to step 4.
^ If stud does not rotate while removing nut, go to step 7.
NOTICE:
Do not over apply threadlocker or allow it to accumulate in bottom of hole. The front cover could be damaged when the stud is installed.
IMPORTANT:
If reinstalling a previously installed stud, the threads must be thoroughly cleaned before applying Loctite 242(R) (P/N 21485277), or equivalent. If installing a new stud, the stud may or may not have a pre-applied threadlocker. The front cover hole must be thoroughly cleaned using a 10 mm x 1.5 mm tap to clean the threads and compressed air to remove particles from the stud hole.
4. Apply Loctite 242(R) (P/N 21485277), or equivalent, to 6-8 middle threads of clean front cover stud.
5. Apply Loctite 242(R) (P/N 21485277), or equivalent, to threads of holes in engine front cover using a cotton tipped applicator keeping top two threads clean.
6. Install stud into front cover.
Torque: 25 N.m (18 ft-lbs)
7. Using ground strap (P/N 21025099), attach one end to engine mount rear stud. Install NEW nut (P/N 21006320).
Torque: 50 N.m (37 ft-lbs)
IMPORTANT:
Use new nut (P/N 21012387) to service all years (1995-1999). The new nut has a lower profile which allows for additional free thread above the nut.
8. Using new nut, (P/N 21012387), attach other end of ground strap to outboard side strut stud.
Torque: 29 N.m (21 ft-lbs)
9. With radio tuned to a fringe AM station and with engine running, verify noise is reduced or eliminated. If noise is not reduced or eliminated, refer to the Audio System section of the appropriate model year Audio System & I/P Cluster service manual and/or Technical Service Bulletins 95-T-28A or 98-T-19.
PARTS REQUIREMENTS:
Wire Asm-Eng Grd 21025099
Nut-Torque Prevailing 21006320
Nut (strut mount) 21012387
Threadlocker (Loctite 242(R)) 21485277
CLAIM INFORMATION:
To receive credit for this repair during the warranty coverage period, submit a claim through the Saturn Dealer System as shown.
IMPORTANT:
If Threadlocker is billed to the customer service order (CSO), the part amount may not exceed $1.15 (includes 30% mark-up).