Oil Pump Cleaning and Inspection

WARNING: This page is about a different variant/trim than selected.

Remove the oil pump gear cover bolts.
Remove the oil pump gear cover.

Fig 1: View Of Oil Pump Gear Cover & Bolts
Courtesy of GENERAL MOTORS CORP.
Use a feeler gauge to measure the clearance between the gear teeth and the oil pump housing. The production clearance is 0.125-0.221 mm (0.0049-0.0087 in) and the service limit is 0.221 mm (0.0087 in).

Fig 2: Measuring Clearance Between Gear Teeth & Oil Pump Housing
Courtesy of GENERAL MOTORS CORP.
Replace the oil pump assembly if the clearance exceeds the service limit.
Use a feeler gauge and a straightedge to measure the clearance between the side of the gear and the cover. The production clearance is 0.064-0.109 mm (0.0025-0.0043 in) and the service limit is 0.109 mm (0.0043 in).

Fig 3: Measuring Clearance Between Side Of Gear & Cover
Courtesy of GENERAL MOTORS CORP.
Replace the oil pump assembly if the clearance exceeds the service limit.
Calculate the driven gear shaft to bushing clearance.
1. Measure the driven gear shaft outside diameter. The production specification is 19.947-19.960 mm (0.7853-0.7858 in) and the service limit is 19.86 mm (0.7819 in).
2. Measure the driven gear bushing inside diameter. The production value is 20 mm (0.7874 in).
3. Calculate the driven gear shaft to bushing clearance. The service limit is 0.14 mm (0.0055 in)
  
  Fig 4: Measuring Driven Gear Shaft To Bushing Clearance
  Courtesy of GENERAL MOTORS CORP.
Replace the oil pump assembly if the clearance exceeds the service limit.
Install the oil pump gear cover to the oil pump assembly.

Fig 5: View Of Oil Pump Gear Cover & Bolts
Courtesy of GENERAL MOTORS CORP.

NOTE: Refer to FASTENER NOTICE .

Install the oil pump gear cover bolts.
Tighten: Tighten the oil pump gear cover bolts to 21 N.m (15 lb ft).