Express 3/4 Ton Van V8-4.8L VIN V (2003)
incorrect length drive belt(s) was installed. it may not be routed correctly and may be turning an accessory drive component in the incorrect
direction.
7. Misalignment of the accessory drive pulley(s) may be caused from improper mounting or incorrect installation of a accessory drive component or
the pulley may be bent inward or outward from a previous repair. Test for a misaligned pulley using a straight edge in the pulley grooves across
two or three pulleys. If a misaligned pulley is found, refer to that accessory drive component for the proper removal and installation procedure for
that pulley.
8. Inspect the accessory drive pulley(s) to verify that they are the correct diameter or width. Using a known good vehicle. compare the accessory
drive pulleys.
Steps 1 - 9
Drive Belt Squeal Diagnosis
Drive Belt Vibration
Drive Belt Vibration Diagnosis
Diagnostic Aids
The accessory drive components may have an affect on engine vibration. An overcharged air conditioning (A/C) system, a power steering system
restriction, or the incorrect fluid, or an extra load placed on the generator are suggested items to inspect. To help identify an intermittent or an
improper condition, vary the loads on the accessory drive components.
Test Description
The number(s) below refer to the step(s) in the diagnostic table.
2. This test is to verify that the vibration is present during diagnosing. Other vehicle components may cause a similar symptom such as the exhaust
system, or the drivetrain.
3. This test is to verify that the drive belt(s) or accessory drive components may be causing the vibration. Remove the drive belt(s) and operate the
engine for a few seconds, this will verify if the vibration is related to the drive belt(s) or not. With the drive belt(s) removed the water pump will
not operate and the engine may overheat. Also diagnostic trouble codes (DTCs) may set when the engine is operated with the drive belt(s)
removed.
4. The drive belt(s) may cause a vibration. While the drive belt(s) is removed this is the best time to inspect the condition of the drive belt(s).
