Procedure B - Engine Component Imbalance

PROCEDURE B - Engine Component Imbalance

If previous inspections and repairs have not corrected vibration, it may be due to rotating or reciprocating imbalance. These conditions are extremely uncommon. Therefore, the technician should exercise extreme care when proceeding. Review all diagnosis notes and retest as appropriate.
1. Operate engine with all accessory drive belts removed.

CAUTION: Avoid engine overheat, while operating with belts removed.

Exhaust System:

2. Inspect exhaust system at full operating temperature. Look for frame contact and stressed or stretched hangers. Loosen exhaust system flanges and hangers (not manifold to head), engage a forward and reverse gear to rock engine, and retighten all exhaust components. Retest.

Engine Mounting:

3. Loosen engine mount to frame bolts slightly and rock engine in a forward and reverse gear. Stop engine and retighten engine mounts. (See diagram below.)

4. If condition still exists, loosen engine to transmission bolts slightly and rock engine in a forward and reverse gear. Retighten all bolts.

5. If condition still exists, vibration is most likely due to imbalance of rotating components (i.e., clutch, flywheel, torque converter, etc.). Contact regional personnel if further assistance is required in this area.