r
between fan blades and thermometer sensor
before starting engine.
Position thermometer so that the thermometer
sensor is centered in the space between the fan
blades and radiator. This can be achieved by
inserting the sensor through one of the existing
holes in the fan shroud or fan guard, or by placing
between the radiator and the shroud. On some
models, it may be necessary to drill a 3/16" hole in
the fan shroud to insert J6742-01.
D. Cover radiator grille sufficiently to induce a high
engine temperature. Start engine and turn on air
conditioning if equipped. Maintain a position in
front of the vehicle to observe the thermometer
reading. With a rod, broom handle, or etc., push
on the accelerator linkage to maintain approx
imately 3000 r.p.m. Use tachometer if available.
E. Observe thermometer reading when clutch engages.
It will take approximately 5 to 10 minutes for the
temperature to become high enough to allow
engagement of the fan clutch. This will be
indicated by an increase or roar in fan air noise
and by a drop in the thermometer reading of
approximately 5-15 degrees F. If the clutch did not
engage between 165-190 degrees F., the unit should
be replaced.
NOTE: Be sure fan clutch was disengaged at
beginning of test.
CAUTION:
Do not continue test past a
thermometer reading of 190 degrees F to
prevent engine overheating.
If no sharp increase in fan noise or temperature
drop was observed and the fan noise level was
constantly high from start of test to 190 degrees F,
the unit should be replaced.
F. As soon as the clutch engages, remove the radiator
grille cover and turn off the air conditioning to
assist in engine cooling. The engine should be run
at approximately 1500 r.p.m.
G. After several minutes the fan clutch should
disengage, as indicated by a reduction in fan speed
and roar.
Thermostat
A pellet-type thermostat is used in the coolant outlet
passage to control the flow of engine coolant, to provide
fast engine warm-up and to regulate coolant tempera
tures. A wax pellet or powder element in the thermostat
expands when heated and contracts when cooled (Fig. 8).
The pellet is connected through a piston to a valve.
When the pellet is heated, pressure is exerted against a
rubber diaphragm which forces the valve to open. As the
pellet is cooled, the contraction allows a spring to close
the valve. Thus, the valve remains closed while the
coolant is cold, preventing circulation of coolant through
the radiator, but allowing the coolant to circulate
throughout the engine to warm it quickly and evenly.
6 K - 6 E N G I N E C O O L I N G
Fig. 8—Sectional View of Thermostat
As the engine becomes warm, the pellet expands and the
thermostat valve opens, permitting the coolant to flow
through the radiator where heat is passed through the
radiator walls. This opening and closing of the
thermostat valve permits enough coolant to enter the
radiator to keep the engine within operating temperature
limits.
Coolant
Regardless of whether freezing temperatures are or are
not expected, cooling system protection should be
maintained at least to -20°F. to provide adequate
corrosion protection and proper temperature indicating
light operation. With glycol content less than require-
LIGHT DUTY TRUCK SERVICE MANUAL
Summary of Contents for Light Duty Truck 1973
Page 1: ......
Page 4: ......
Page 6: ......
Page 53: ...HEATER AND AIR CONDITIONING 1A 27 LIGHT DUTY TRUCK SERVICE MANUAL...
Page 115: ...LIGHT DUTY TRUCK SERVICE M A N U A L HEATER AND AIR CONDITIONING 1A 89...
Page 123: ...BODY 1B 3 Fig 6 Typical 06 Van LIGHT DUTY TRUCK SERVICE MANUAL...
Page 149: ...BODY 1B 29 Fig 84 Body Mounting 06 Fig 85 Body Mounting 14 LIGHT DUTY TRUCK SERVICE MANUAL...
Page 171: ...LIGHT DUTY TRUCK SERVICE M A N U A L Fig 2 Frame Horizontal Checking Typical FRAME 2 3...
Page 173: ...LIGHT DUTY TRUCK SERVICE M A N U A L Fig 4 10 30 Series Truck Frame FRAME 2 5...
Page 174: ...2 6 FRAME LIGHT DUTY TRUCK SERVICE MANUAL Fig 5 Underbody Reference Points G Van...
Page 185: ...FRONT SUSPENSION 3 11 Fig 16 Toe out on Turns LIGHT DUTY TRUCK SERVICE MANUAL...
Page 224: ......
Page 266: ......
Page 351: ...ENGINE 6 15 Fig ID Sectional View of Eight Cylinder Engine LIGHT DUTY TRUCK SERVICE MANUAL...
Page 375: ...EN G IN E 6 39 LIGHT DUTY TRUCK SERVICE MANUAL...
Page 376: ...6 4 0 ENGINE LIGHT DUTY TRUCK SERVICE MANUAL...
Page 377: ...ENG IN E 6 41 LIGHT DUTY TRUCK SERVICE MANUAL...
Page 378: ...LIGHT DUTY TRUCK SERVICE MANUAL Fig 37L K Series Engine Front Mount 6 42 ENG INE...
Page 400: ...6 6 4 ENG INE LIGHT DUTY TRUCK SERVICE MANUAL...
Page 401: ...ENG IN E 6 65 LIGHT DUTY TRUCK SERVICE MANUAL...
Page 402: ...6 6 6 ENGINE LIGHT DUTY TRUCK SERVICE MANUAL...
Page 403: ...E NG IN E 6 67 Fig 36V C Series Engine Mounts LIGHT DUTY TRUCK SERVICE MANUAL...
Page 410: ......
Page 423: ...EN G IN E C OOLING 6K 13 Fig 16 Overheating Chart LIGHT DUTY TRUCK SERVICE MANUAL...
Page 424: ...6 K 1 4 ENG INE COOLING Fig 17 Coolant Loss Chart LIGHT DUTY TRUCK SERVICE MANUAL...
Page 456: ...6M 32 ENGINE FUEL Fig K15 Accelerator Controls G Van L 6 LIGHT DUTY TRUCK SERVICE MANUAL...
Page 492: ......
Page 512: ...Fig 18e Vacuum Advance Diagram V8 Engine...
Page 516: ...6 T 2 4 E M IS S IO N CONTROL SYSTEMS LIGHT DUTY TRUCK SERVICE MANUAL...
Page 528: ......
Page 590: ......
Page 593: ...CLUTCHES MANUAL TRANSMISSIONS 7M 3 LIGHT DUTY TRUCK SERVICE MANUAL...
Page 598: ...7M 8 CLUTCHES MANUAL TRANSMISSIONS LIGHT DUTY TRUCK SERVICE MANUAL...
Page 642: ......
Page 654: ......
Page 743: ...FUEL TANKS AND EXHAUST 8 13 LIGHT DUTY TRUCK SERVICE MANUAL...
Page 744: ...8 14 FUEL TANKS AND EXHAUST LIGHT DUTY TRUCK SERVICE MANUAL...
Page 760: ...8 30 FUEL TANKS AND EXHAUST Fig 40 Exhaust Pipe P Models LIGHT DUTY TRUCK SERVICE MANUAL...
Page 761: ...FUEL TANKS AND EXHAUST 8 31 LIGHT DUTY TRUCK SERVICE MANUAL...
Page 763: ...FUEL TANKS AND EXHAUST 8 33 LIGHT DUTY TRUCK SERVICE MANUAL...
Page 766: ......
Page 832: ...LIGHT DUTY TRUCK SERVICE MANUAL Fig 106 Power Steering Pump Mounting Typical 9 66 STEERING...
Page 833: ...PUMP ASSEMBLY STEERING GEAR TYPICAL SMALL V8 TYPICAL LARGE V8 STEERING 9 67...
Page 861: ...STEERING 9 95 Fig 134 Power Steering Pump Leakage LIGHT DUTY TRUCK SERVICE MANUAL...
Page 864: ......
Page 876: ......
Page 886: ...11 10 CHASSIS SHEET METAL LIGHT DUTY TRUCK SERVICE MANUAL...
Page 891: ...ELECTRICAL BODY AND CHASSIS 12 5 LIGHT DUTY TRUCK SERVICE MANUAL...
Page 934: ......
Page 942: ......
Page 970: ......
Page 972: ......
Page 974: ......
Page 976: ...V...
Page 978: ......
Page 979: ......