LSS V6-3.8L VIN K (1997)
Balance Shaft: Testing and Inspection
Rattle
Balance shaft rattle sounds like a tiny, chattery rattle or a knocking noise that seems to come from the top rear of the engine. This noise is most
pronounced when the engine is hot, and is not affected by engine load. An example would be dirt lodged in the root between two gear teeth. Each time
the root between two balance shaft gear teeth meshes with a cam gear tooth, the balance shaft is momentarily forced upward. This pivots the shaft
through the front bearing, causing a downward force on the rear bearing that eventually wears the rear bearing, causing a rattle. The following are other
factors that contribute to balance shaft bearing rattle:
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A tight link on the timing chain
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Damaged, broken, or dirty teeth on the balance shaft gears.
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A worn timing chain tensioner.
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Misaligned rear balance shaft bushing.
