Exhaust - Hoot or Moan Noise During Steady Throttle
BULLETIN NO.: 97-T-46ISSUE DATE: November, 1997
GROUP/SEQ. NO.: Chassis-03
CORPORATION NO.: 786602
SUBJECT:
"Hoot" or "Moan" Noise During Steady Throttle with Engine Speed Between 1800-1850 RPM (Install Additional Exhaust Clamps on Intermediate Exhaust Pipe)
MODELS AFFECTED:
1991-1997 Saturns
CONDITION:
Some customers may comment about a "Hoot" or "Moan" noise from the exhaust with the engine speed between 1800-1850 RPM. The customer may comment that the noise is coming from the rear of the vehicle. This noise is present during a narrow RPM range and during balanced throttle or light throttle deceleration. The noise may be most noticeable in vehicles equipped with automatic transaxles at 64-81 km/h (40-50 mph) with TCC applied, and in vehicles equipped with manual transaxles in 3rd or 4th gear at 1800-1850 RPM. This noise can also be heard with the vehicle stopped in Neutral or Park and the engine speed between 1800-1850 RPM.
CAUSE:
The noise is caused by exhaust system resonance.
CORRECTION:
The installation of the additional exhaust clamps will add mass to the intermediate exhaust pipe and cause it to resonate at a frequency that is not audible to the customer. Refer to the following procedure for the correct placement of the additional exhaust clamps.
PROCEDURE
1. Raise vehicle.
2. Install two exhaust clamps on the straight section of the intermediate exhaust pipe forward of, and parallel to the front of the fuel tank, 100 mm (4 in.) from the outboard bend of the intermediate exhaust pipe as shown in illustration.
3. Align the exhaust clamps as shown in illustration.
4. Lower vehicle.
5. Verify customer's concern has been repaired.
PARTS REQUIREMENTS:
25517280 Clamp-Exh Muff (2-Required)
CLAIM INFORMATION:
To receive credit for this repair during the warranty coverage period, submit a claim through the Saturn Dealer System as shown.