Hummer H2. Manual - part 69

Fig. 28: Installing Typical Rope Seal 

Split-Rubber Type Seal 

Follow manufacturer's procedures when installing split-rubber type rear main oil seals. Installation procedures 
vary with manufacturer and engine type. See Fig. 29 .  

Fig. 29: Installing Typical Split-Rubber Seal

 

1998 Chevrolet Pickup C1500 

GENERAL INFORMATION Engine Overhaul Procedures

  

OIL PUMP 

ROTOR TYPE 

Mark oil pump rotor locations before removing. See Fig. 30 . Remove outer rotor and measure thickness and 
diameter. Measure inner rotor thickness. Inspect shaft for scoring or wear. Inspect rotors for pitting or damage. 
Inspect cover for grooving or wear. Replace worn or damaged components.  

Measure outer rotor-to-body clearance. Replace pump assembly if clearance exceeds specification. Measure 
clearance between rotors. See Fig. 31 . Replace shaft and both rotors if clearance exceeds specification.  

Install rotors in pump body. Position straightedge across pump body. Using feeler gauge, measure clearance 
between rotors and straightedge. Pump cover wear is measured using a straightedge and feeler gauge. Replace 
pump if clearance exceeds specification.  

Fig. 30: Typical Rotor Type Oil Pump 

 

1998 Chevrolet Pickup C1500 

GENERAL INFORMATION Engine Overhaul Procedures

  

Fig. 31: Measuring Rotor Clearance 

GEAR TYPE 

Mark oil pump gear location before removing. See Fig. 32 . Remove gears from pump body. Inspect gears for 
pitting or damage. Inspect cover for grooving or wear. Measure gear diameter and length. Measure gear housing 
cavity depth and diameter. See Fig. 33 . Replace worn or damaged components.  

Pump cover wear is measured using a straightedge and feeler gauge. Replace pump or components if warpage 
or wear exceeds specification, or mating surface of pump cover is scratched or grooved.  

 

1998 Chevrolet Pickup C1500 

GENERAL INFORMATION Engine Overhaul Procedures

  

Fig. 32: Typical Gear Type Oil Pump 

Fig. 33: Measuring Oil Pump Gear Cavity 

BREAK-IN PROCEDURE 

ENGINE PRE-OILING 

Pre-oil engine prior to operation to prevent engine damage. Lightly oiled oil pump will cavitate unless oil pump 
cavities are filled with engine oil or petroleum jelly.  

Engine pre-oiling can be done using pressure oiler (if available). Connect pressure oiler to cylinder block oil 
passage such as oil pressure sending unit. Operate pressure oiler long enough to ensure correct amount of oil 
has filled crankcase. Check oil level while pre-oiling.  

If pressure oiler is not available, disconnect ignition system. Remove oil pressure sending unit and replace with 
oil pressure test gauge. Using starter motor, rotate engine starter until gauge shows normal oil pressure for 
several seconds. DO NOT crank engine for more than 30 seconds to avoid starter motor damage. Ensure oil 
pressure has reached the most distant point from the oil pump.  

NOTE:

If new lifters or camshaft are installed, some manufacturers require that a 

 

1998 Chevrolet Pickup C1500 

GENERAL INFORMATION Engine Overhaul Procedures