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