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Starter Noise

CAUTION: Never operate starter for periods of more than 15 seconds. Excessive cranking can cause starter to overheat. Allow starter to cool for at least 2 minutes after each time operated.
NOTE: Check flywheel ring gear for damage.
  1. A high-pitched whine, heard while cranking (before engine starts), indicates excessive distance between starter pinion and flywheel. If high-pitched whine is heard after engine starts and key is released, distance between starter pinion and flywheel is too small. Locate high spot on flywheel before checking pinion-to-flywheel clearance. Pinion-to-flywheel clearance should be .020" (0.5 mm). See Fig 1.
  2. If loud, siren-like whoop sound is heard after the engine starts, drive assembly is likely defective. If rumble, growl or knock is present as starter is coasting to a stop after starting engine, starter armature is bent or unbalanced.
  3. If diagnosis indicates pinion should be closer to flywheel, ensure proper starter motor was installed. During initial starter motor installation, shim(s) are not used. If shim(s) are present, remove as necessary.
  4. If diagnosis indicates starter should be moved away from flywheel, add shims as necessary. If using .039" (1.0 mm) long shims, do not exceed 2 shims. If using .015" (.38 mm) long shims, do not exceed 3 shims. If condition is not corrected, and pinion-to-flywheel clearance has been reached, short shims may be added to outer side of starter motor bolt using .015" (.38 mm) shims. For starter removal, see STARTER under REMOVAL & INSTALLATION .
Fig 1: Measuring Pinion-To-Flywheel Clearance
G90I04573Courtesy of GENERAL MOTORS CORP.