Cooling System - Hummer H1 Service Manual

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2-2 Engine
Oil Pump
Oil Pump and Drive Removal . . . . . . . . . . . . . . . . . . . . . . .2-58
Oil Pump and Pump Drive Service. . . . . . . . . . . . . . . . . . .2-77
Oil Pump Drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-22
Oil Pump Pressure. . . . . . . . . . . . . . . . . . . . . . . . . . . . Test 2-7
Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-28
Oil Pump, Oil Pan, Flywheel Installation . . . . . . . . . . . . . . . . . .2-84
Piston/Connecting Rod
Installation and Bearing Fit. . . . . . . . . . . . . . . . . . . . . . . . .2-83
Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-59
Piston/Connecting Rod Overhaul . . . . . . . . . . . . . . . . . . . . . . .2-67
Piston and Connecting Rod Assembly . . . . . . . . . . . . . . .2-69
Piston Ring Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . .2-70
Piston Selection and Fit . . . . . . . . . . . . . . . . . . . . . . . . . . .2-68
Power Steering Pump and Bracket . . . . . . . . . . . . . . . . . . . . . .2-50
Pushrod, Rocker Arm and Shaft Installation . . . . . . . . . . . . . .2-90
Rear Main Oil Seal Replacement . . . . . . . . . . . . . . . . . . . . . . . .2-29
Rear Main Seal Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-82
Road Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-5
Rocker Arm
Cover Removal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-54
Cover Service. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-30
Shaft and Pushrod Removal. . . . . . . . . . . . . . . . . . . . . . . .2-54
Shaft and Pushrod Service . . . . . . . . . . . . . . . . . . . . . . . . .2-33
Rocker Cover Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-91
ENGINE DESCRIPTION
A turbocharged diesel engine is used in Hummer vehicles. It is
a liquid cooled, four-stroke, 90¡ Ð V8 engine with a displace-
ment of 6.5L (395 cu. in.) (Figure 2-1). The engine is manufac-
tured by General Motors Corporation.
Figure 2-1: 6.5L Turbo Diesel Engine
Engine Components
The engine block and cylinder heads are cast iron. Turbo en-
gines are equipped with a three-piece aluminum intake mani-
fold and cast iron exhaust manifolds.
The oil cooling system for turbo diesel pistons provides for oil
spray onto the underside of the piston crown. This is accom-
plished by additional oil feed orifice tubes and galleries in the
block. Oil spray occurs when the piston is approaching bottom
Serpentine Belt Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-49
Timing Chain/Drive Sprockets/Drive Gear . . . . . . . . . . . . . . . . 2-57
Timing Chain-Sprocket-Gear Installation . . . . . . . . . . . . . . . . . 2-85
Torsional Damper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-21
Torsional Damper/Crankshaft Pulley . . . . . . . . . . . . . . . . . . . . 2-93
Turbocharger
Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-18
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-17
Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-16
Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-17
Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-16
Service and Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-15
Turbocharger and Center Manifold Removal . . . . . . . . . . . . . . 2-52
Turbocharger and Intake Manifold . . . . . . . . . . . . . . . . . . . . . . 2-93
Vacuum Pump Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-44
Valve Lifter
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-88
Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-55
Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-41
Water Crossover
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-92
Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-52
Water Pump and Adapter Plate Installation . . . . . . . . . . . . . . . 2-87
Water Pump and Adapter Plate Removal . . . . . . . . . . . . . . . . . 2-56
dead center on the intake and power strokes. The extra oil pres-
sure and volume needed for piston cooling is provided by a
high output oil pump. The pump has a working pressure of 80
psi (552 kPa). Oil feed for piston spray is through galleries and
oil tubes located in the main bearing saddles and webs.
The crankshaft is supported by five insert style main bearings.
Thrust is taken by the number 3 main. The camshaft is also
supported by five bearings; plain type bearings are used.
The engine is equipped with three ring aluminum pistons. Con-
necting rods are forged steel. The pistons are attached to the
rods with hardened steel piston pins. Each piston pin is re-
tained by two snap rings; one at each end of the pin. The pin is
a floating fit in the rod and piston.
A single chain driven camshaft operates the overhead valve
train. Roller lifters and tubular push rods actuate the rocker arms.
The arms are mounted on shafts bolted to each cylinder head.
The cylinder heads are equipped with glow plugs for each cyl-
inder and a prechamber for each combustion chamber. One
plug and one prechamber are used in each combustion cham-
ber. The glow plugs heat air entering the prechambers. This
aids the combustion process and improves cold weather start-
ing and operation. The glow plugs are activated only when am-
bient temperatures fall below a pre-set value. On the turbo
diesel engine the glow plug relay is mounted on the intake
manifold and is controlled by the PCM.
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