GMC 4000 Series Service Manual page 276

GENERAL
Two types of engines, namely "In-line" and
"V6" are mounted in different manner, hence, the
procedures required to remove and install each
type of engine will differ. Also, the operations re­
quired to replace engines will vary between models,
i.e ., conventional, tilt-cab, and "P" models.
IN-LINE ENGINES IN CONVENTIONAL
A N D SCHOOL BUS MODELS
ENGINE REMOVAL
1. Drain radiator.
2. Disconnect battery.
3. Remove hood attaching parts and remove
hood.
4. Remove braces which support grille and
radiator assembly.
5. Remove radiator hoses and heater hoses.
6. Remove radiator and grille assembly. Re­
fer to SHEET METAL (SEC. 11) of this manual for
necessary information when removing grille and
radiator assembly.
7. Disconnect fuel line at fuel pump.
8. Remove air cleaner and cover carburetor
air inlet opening to prevent entrance of dirt.
9. Disconnect choke control and accelerator
linkage.
10. Disconnect exhaust pipe from manifold.
11. Disconnect wiring harness and battery
cable.
12. Remove floor mat and transmission cover
from cab floor, then remove hand brake lever and
gearshift lever from transm ission.
13. Disconnect propeller shaft from trans­
m ission flange.
14. Attach lifting equipment to take weight of
power plant off mountings, then remove mounting
bolts and remove rear crossmember which is
bolted in place.
15. Lift engine and transm ission out of chassis
as an assembly.
16. Refer to TRANSMISSIONS AND CLUTCHES
(SEC. 7) for necessary information to remove
transm ission and clutch from engine.
ENGINE INSTALLATION
1. Refer to TRANSMISSIONS AND CLUTCHES
(SEC. 7) for information necessary to install clutch
and transmission on engine.
2. Attach lifting equipment and lift power plant
G M C S E R V I C E M A N U A L
Zncjine Replacem ent
into place in chassis. Install support crossmember
and install engine mountings. Refer to ENGINE
MOUNTINGS (SEC. 6D) of this manual for required
information regarding engine mountings.
then install cover in cab above transmission.
electrical wiring connections, and connect carbur­
etor control linkage.
ferring to SHEET METAL (SEC. 11) for necessary
information for fitting hood.
fill cooling system .
dipstick, referring to LUBRICATION (SEC. 0) in
this manual for recommended type and viscosity.
trical equipment.
and oil leaks.
(IN-LINE ENGINE IN PS4500 MODEL)
REMOVAL
from battery.
panel between step w ells.
and pedals.
and choke controls. Disconnect wiring and fuel
supply line.
from engine. Remove radiator, radiator support
and shroud, referring to RADIATOR AND SURGE
TANK (SEC. 13) of this manual for necessary in­
formation.
damage when removing engine. Disconnect clutch
control linkage.
remove rocker arm cover.
transm ission assembly.
engine and remove from vehicle.
GASOLINE ENGINES
3. Connect propeller shaft and hand brake.
4. Install handbrake lever and gearshift lever,
5. Connect exhaust pipes to manifolds, make
6. Install front end sheet metal and hood, re­
7. Install air cleaner, connect fuel line, and
8. Fill crankcase with oil to proper level on
9. Install battery and check operation of elec­
10. Start engine and check for coolant leaks
ENGINE REPLACEMENT
1. Remove engine cover and disconnect cables
2. Remove driver's seat and remove floor
3. Remove seal plates around steering shaft
4. Remove air cleaner and disconnect throttle
5. Disconnect exhaust pipe from manifold.
6. Disconnect radiator hose and heater hose
7. Remove fan blade assembly to prevent
8. Disconnect crankcase ventilation hoses and
9. Attach crane-type hoist to engine.
10. Support power plant on hoist and remove
11. Remove engine mounting bolts, then lift
Sec. 6A
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