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7 - 8
COOLING SYSTEM
•
COOLING SYSTEM
D I A G N O S I S - C O N T I N U E D
Condition and Check
Diagnosis
POOR HEATER PERFORMANCE. SUSPECT
THERMOSTAT FAILED IN OPEN POSITION.
(1) Does gauge read low?
(2) Is coolant level low?
(3) Check On-Board Diagnostics. Is code 17 set in memory?
(1) If YES, replace thermostat. If NO, inspect the auxiliary heater
vacuum water valve. The valve should be open except when the
climate controls are OFF or in the MAX A/C mode.
(2) Fill cooling system and inspect for leaks. Repair as necessary.
(3) If YES, replace thermostat. If NO, inspect the auxiliary heater
vacuum water valve. The valve should be open except when the
climate controls are OFF or in the MAX A/C mode.
J9007-61
S E R V I C E P R O C E D U R E S
INDEX
Page
Coolant
. . . . . . . . . . . .
11
Coolant Reserve System ( C R S )
.
. 15
Cooling System Cleaning, Reverse Flushing . . . . . 13
Cooling System Fan
19
Cooling System Hoses
18
Draining Cooling System
12
Engine Thermostat
10
WATER PUMPS
A centrifugal w a t e r p u m p circulates t h e coolant
t h r o u g h the w a t e r jackets, passages, i n t a k e manifold,
radiator core, cooling system hoses and heater core.
The pump is d r i v e n f r o m the engine crankshaft b y a
" V " drive belt.
The water p u m p i m p e l l e r i s pressed onto the rear
of a shaft t h a t rotates i n a b e a r i n g pressed into t h e
w a t e r pump body. The body has a s m a l l hole to allow
seepage t o escape. T h e w a t e r p u m p seals are l u b r i -
cated b y t h e antifreeze i n t h e coolant m i x t u r e . N o
additional l u b r i c a t i o n i s necessary.
A quick test t o t e l l w h e t h e r or not t h e p u m p is
w o r k i n g is t o check i f t h e heater w a r m s properly. A
defective water p u m p w i l l n o t be able to circulate
heated coolant t h r o u g h the l o n g heater hose t o t h e
heater core.
Page
Pressure Testing Radiator Caps
. . . . . . . . . . . . . .
16
Radiator
17
Radiator Pressure Cap
16
Refilling The Cooling System
13
Testing Cooling System For Leaks
14
Transmission Oil Cooler
. 18
Water Pumps .
8
The w a t e r p u m p o n a l l models can be removed
w i t h o u t discharging the a i r conditioning system.
WATER PUMP REMOVAL-ALL
ENGINES
I f the w a t e r p u m p is replaced because of b e a r i n g or
shaft damage, t h e mechanical cooling f a n should be
inspected for fatigue cracks, loose blades, or loose r i v -
ets t h a t could have resulted f r o m excessive v i b r a t i o n .
Replace t h e f a n i f any o f these conditions are found.
The w a t e r p u m p can be removed a n d i n s t a l l e d
w i t h o u t discharging the a i r conditioning system.
(1) D r a i n cooling system.
(2) I f equipped w i t h air-conditioning, remove t h e
radiator. Refer t o Radiator Removal i n t h i s section.
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