Pontiac FIREBIRD 1972 Service Manual page 621

SECTION 6 A
ENGINE COOLING AND LUBRICATION
CONTENTS OF THIS SECTION
Trouble Diagnosis
-
Engine Cooling System
..........
6A-2
Fan Clutch Diagnostic Procedure
..........................
6A-1
General Description
................................................
6A-5
Engine Cooling System
..................................
6A-5
Radiator
................................................................
6A-5
Radiator Cap
........................................................
6A-5
Water Pump-8 cyl.
........................................
6A-7
Water Pump-6 cyl.
........................................
6A-7
Fan
........................................................................
6A-7
Power Flex
......................................................
6A-9
Fluid Clutch
....................................................
6A-9
Thermostat
........................................................
6A- 10
Circulation
..........................................................
6A- 10
8 cyl.
..............................................................
6A-10
6 cyl.
..............................................................
6A-11
............................................
Service Operations 6A- 11
Engine Lubrication System
..................................
6A- 18
............................................................
Oil Pump 6A-18
..............................................................
8 cyl. 6A-18
..............................................................
6 cyl. 6A-18
..........................................................
Circulation 6A- 18
..............................................................
8 cyl. 6A-18
..............................................................
6 cyl. 6A-22
............................................
Service Operations 6A-22
................................
Accessory Drive lnstalldtion 6A-24
Drive Belt Chart and Adjustments
......................
6A-25
............................................
Fan Types and Usage 6A-31
......................................................
Radiator Usage 6A-32
............................................
Torque Specifications 6A-33
Cooling and Lubrication System
..........................................................
Specifications 6A-33
..........................................................
Special Tools 6A-33
TROUBLE DIAGNOSIS
FAN CLUTCH DIAGNOSTIC PROCEDURE 3. SILICONE FLUID LEAK
1. NOISE
Fan noise is sometimes evident under the following
normal conditions:
a. when clutch is engaged for maximum cooling and
b. during first few minutes after start-up until the
clutch can re-distribute the silicone fluid back to
its normal disengaged operating condition after
overnight settling.
The operation of the unit is generally not affected by
small fluid leaks which may occur in the area around
the bearing assembly. However, if the degree of leak-
age appears excessive, proceed to item 4.
4. ENGINE OVERHEATING
a. Start with a cool engine to insure complete fan
clutch disengagement.
NOTE: Refer to Item I, paragraph I .
b. If the fan and clutch assembly free-wheels with no
However, fan noise or an excessive roar will generally
drag (revolves over 5 times when spun by hand),
occur continuously under all high engine speed con-
the clutch should be replaced. If clutch performs
ditions (2500 r.p.m. and up) if the clutch assembly is
properly with a slight drag go to step c.
locked up due to an internal failure. If the fan cannot
be rotated by hand or there is a rough grating feel as
the fan is turned, the clutch should be replaced.
2. LOOSENESS
Under various temperature conditions, there is a visi-
ble lateral movement that can be observed at the tip
of the fan blade. This is a normal condition due to the
type of bearing used. Approximately 1/4" maximum
lateral movement measured at the fan tip is allowa-
ble. This is not cause for replacement.
NOTE: Testing a fan clutch by holding the
small hub 'with one hand and rotating the
aluminum housing in a clockwise/counter-
clockwise motion will cause the clutch to free-
wheel, which is a nonnal condition when
operated in this manner. This should not be
considered a test by which replacement is deter-
mined.
c. Use dial type thermometer J 6742-01, or similar
type.