GM Service Manual Online
For 1990-2009 cars only

Tools Required

J 9666 Valve Spring Tester

Inspection Procedure

  1. Clean the valve springs in solvent.
  2. Caution: Wear safety glasses in order to avoid eye damage.

  3. Dry the valve springs with compressed air.
  4. Inspect the valve springs for broken coils or coil ends.

Measurement Procedure


    Object Number: 4960  Size: SH
  1. Measure the valve spring tension using the J 9666 . Refer to Engine Mechanical Specifications .
  2. If low valve spring load is found, replace the valve springs. DO NOT use shims to increase spring load. The use of shims will cause the valve spring to bottom out before the camshaft lobe is at peak lift.