Bonneville V6-231 3.8L VIN 3 SFI (1988)
FIGURE 5
If component fore-aft location is acceptable, then a component or pulley could be out of plane or "cocked", (see Figure 5).
In some instances, a component can be brought back into plane by shimming, if the mounting locations correspond to a direction that is correct for
realignment; otherwise, the component or bracket may need to be replaced.
If all alignments check out to be acceptable, and there is still belt noise, check all related component bearings to be sure they turn freely and do not drag.
The tensioner arm should also be checked for freedom of movement.
If it is necessary to replace a drive belt due to excessive wear, irregular splice (causing belt hop), excessive paint build up on the back side of the belt
(from painted pulleys) or a belt contaminated with excessive belt dressing; make sure the latest design belt is installed.
Automatically tensioned SBAD belts are not generally noisy unless there is a misalignment or severe loading condition, such as a defective bearing. Belt
dressings are only a "band aid" for a short period of time, and may only conceal the real problem which could drastically shorten belt life.
