GM Service Manual Online
For 1990-2009 cars only

Tools Required

EN 46121 Connecting Rod Guide Pin Set

    Important: 

       • An arrow/dot showing correct piston orientation is located on the top of the piston.
       • If the connecting rod bearings have been used in a running engine, you must replace them with NEW connecting rod bearings for reassembly.

  1. Before removing the connecting rods, check the connecting rod side clearance using the following procedure:
  2. 1.1. Tap the connecting rod to one end of the crankshaft journal with a dead-blow or wooden hammer.
    1.2. Using feeler gages, measure the clearance between the crankshaft counterweight and the connecting rod.
    1.3. The connecting rod side clearance should not exceed specifications. Refer to Engine Mechanical Specifications .
    1.4. If the end play exceeds the specified limits, measure the width of the crankpin end of the connecting rod. Refer to Piston, Connecting Rod, and Bearing Cleaning and Inspection .
    1.5. If the connecting rod width is significantly smaller than specified and extreme wear is present on the side of the connecting rod, replace the connecting rod.
    1.6. If the connecting rod width is within specification and scoring above acceptable tolerances is present on the crankshaft journals, replace the crankshaft.
  3. Using a marker, number each piston face. Draw an arrow along the centerline of the piston pointing toward the front of the cylinder block.
  4. Notice: Refer to General Repair Instructions in the Preface section.

  5. Mark the cylinder number on the connecting rod and the connecting rod cap with a scribe, paint stick or permanent marker.
  6. Notice: Refer to General Repair Instructions in the Preface section.


    Object Number: 1958881  Size: SH
  7. Remove the connecting rod bolts (1).
  8. Important: The connecting rod caps (2) must remain with the original connecting rod.

  9. Remove the connecting rod cap (2).

  10. Object Number: 1958884  Size: SH
  11. Install the EN 46121  (1) into the connecting rod bolt holes.

  12. Object Number: 1958887  Size: SH
  13. Using the EN 46121 1 (1), push the connecting rod and piston assembly (2) through the top of the cylinder. DO NOT scratch the crankshaft journal or cylinder wall and DO NOT damage the oil jets when removing the connecting rod and piston assembly (2).

  14. Object Number: 1958890  Size: SH
  15. Remove the EN 46121  (1) from the connecting rod bolt holes.
  16. Remove the upper connecting rod bearing (3) from the connecting rod (2).

  17. Object Number: 1958892  Size: SH
  18. Remove the lower connecting rod bearing (1) from the connecting rod cap (2).

  19. Object Number: 1958894  Size: SH
  20. Reattach the connecting rod cap (1) to the connecting rod (2) to prevent damage to their mating surfaces. The connecting rod cap (1) and connecting rod (2) are a matched set and must be kept together.