Oil Pump Inspection

NOTE: Tools Required: Feeler Gauge Set (SA91101NE).

Inspect body clearance:
1. Using a feeler gauge set (or equivalent), measure the clearance between the driven rotor and pump body.
  
  Fig 1: Measuring Clearance Between Driven Rotor & Pump Body
  Courtesy of GENERAL MOTORS CORP.
  
  Driven Rotor-To-Pump Body Side Clearance
  - Standard: 0.150-0.277 mm (0.006-0.011 in.)
  - Service Limit: 0.277 mm (0.011 in.) max.
2. If the clearance is greater than service limit, replace oil pump assembly.
Inspect tip clearance:
1. Using a feeler gauge (or equivalent), measure the clearance between both rotor tips.
  
  Fig 2: Inspecting Tip Clearance
  Courtesy of GENERAL MOTORS CORP.
  
  Rotor Tip Clearance
  - Service Limit: 0.150 mm (0.006 in.) max.
2. If the clearance is greater than service limit, replace oil pump assembly.
Inspect end-to-end clearance:
1. Using a feeler gauge (or equivalent) or Plastigage(tm) (or equivalent) measure the clearance between the side of drive and driven rotors and the oil pump cover plate.
  
  Fig 3: Inspecting End-To-End Clearance
  Courtesy of GENERAL MOTORS CORP.
  
  Rotor-To-Cover Side Clearance
  - Standard: 0.040-0.125 mm (0.0016-0.0049 in.)
  - Service Limit: 0.08 mm (0.003 in.) max.
2. If the clearance is greater than service limit, replace oil pump assembly.