Engine - Vibration at 1100-1300 RPM Range

9222buick01

Bulletin
88-6-30

Date
May, '89

Ref. No.
88-274-6

Corp. Ref. No.
906102


SUBJECT:
ENGINE VIBRATION 1100-1300 RPM RANGE


MODELS AFFECTED:
1986-1988 LESABRES AND ELECTRAS WITH 3.8L LG3 V6 ENGINE (VIN CODE 3)


Some 1986-88 LeSabres and Electra models equipped with a 3.8L engine may exhibit a shake/vibration in the 1100-1300 engine rpm range. The condition could be described as a shake/vibration from the floor pan, seat, steering wheel and/or instrument panel at slow speeds (0-15 mph) or as a shudder/chuggle at speeds of 45-55 mph with the Torque Converter Clutch (TCC) engaged. To effectively minimize this condition, use the following repair procedure:

1. Verify engine performance

^ All cylinders firing correctly
^ Expected normal ALDL scan tool readings

2. Check engine mounts for ground out or stress condition. If vehicle is a
1986 LeSabre model, refer to bulletin 86-6-9A for additional information.

3. Remove the engine crankshaft balancer and install a new balancer, part number 25532179. (If vehicle is a 1986 model, a longer crankshaft balancer bolt, part number 25530415, must be installed with the new balancer.

NOTICE:
To ensure the interrupter ring on the new balancer has not been damaged prior to installation, use Kent-Moore Crankshaft Sensor Adjusting Tool J-37089 to check concentricity of the interrupter ring and for correct crankshaft sensor adjustments.

Torque balancer bolt and washer to 270 N-m (200 lbs.ft.)

Parts are currently available from GMSPO

4. Disconnect the exhaust pipe from the exhaust manifold. Using a high temperature anti-seize compound, lubricate the exhaust pipe seal (donut) and reinstall the pipe.





5. Remove the intermediate exhaust pipe hanger and rubber insulators. Refer to figure. Bend the hanger ends upward 1/2". Lubricate the rubber insulators with silicone grease and reinstall the hanger and insulators.

WARRANTY INFORMATION

Labor Operation Number:
T5186
Labor Time:
.8 Hours
Trouble Code:
92