Oil Pump Inspection

TOOLS REQUIRED 

• SA91101NE Feeler Gauge

1. Inspect body clearance:
   1. Using a Feeler Gauge SA91101NE (or equivalent), measure the clearance between the driven rotor and pump body.

      Body to Side Clearance 

      Service Limit: 0.277 mm (0.011 in.) max. 

      Fig 1: Measuring Driven Rotor-To-Pump Body Clearance

      Courtesy of GENERAL MOTORS CORP.
   2. If the clearance is greater than maximum, replace the oil pump assembly.
2. Inspect tip clearance:
   1. Using a feeler gauge SA 91101NE (or equivalent), measure the clearance between both rotor tips.

   Clearance 

   Standard: 0.150 mm (0.006 in.) max. 

   Fig 2: Measuring Clearance Between Rotor Tips

   Courtesy of GENERAL MOTORS CORP.
3. Inspect inner end outer gear-to-housing clearance:
   1. Using a feeler gauge SA 91101NE (or equivalent) or Plastigage® (or equivalent) and straight edge, measure the oil pump inner and outer gear to housing clearance.

   Inner Gear-to-Housing Clearance 

   Service Limit: 0.08 mm (0.003 in.) max. 

   Outer Gear-to-Housing Clearance 

   Service Limit: 0.10 mm (0.004 in.) max. 

   Fig 3: Measuring Oil Pump Inner & Outer Gear-To-Housing Clearance

   Courtesy of GENERAL MOTORS CORP.
4. Inspect oil pressure regulating valve, oil pressure relief valve and springs for wear and damage. Check oil pump pressure regulating valve and oil pressure relief valve for free movement in bores. Replace if worn, damaged or if valves do not move freely in bores.

Fig 4: Inspecting Oil Pressure Regulator & Relief Valves & Components For Damage

Courtesy of GENERAL MOTORS CORP.