Table of Contents
Advertisement
•
COOLING SYSTEM
7 - 1 5
WARNING: WITH PRESSURE TESTER TOOL 7700-A
INSTALLED ON RADIATOR DO NOT ALLOW PRES-
SURE TO EXCEED 110 KPA (20 PSI). PRESSURE
WILL BUILD UP QUICKLY IF A COMBUSTION LEAK
IS PRESENT. TO R E L E A S E THE PRESSURE, ROCK
THE
TESTER FROM SIDE TO SIDE. WHEN REMOV-
ING THE TESTER, DO NOT TURN THE TESTER
MORE THAN 1/2 TURN IF THE SYSTEM IS UNDER
PRESSURE.
Operate t h e engine w i t h o u t t h e pressure cap on the
radiator u n t i l the thermostat opens. A t t a c h a Pres-
sure Tester to the filler neck. I f t h e pressure builds
up q u i c k l y i t indicates a combustion leak exists usu-
a l l y t h e r e s u l t of cylinder head gasket leak or crack
i n the engine. Repair as necessary.
I f there i s no immediate pressure increase, pump
the Pressure Tester u n t i l the indicated pressure is
w i t h i n t h e system range of 110 k P a (16 psi). F l u c t u -
ation o f t h e gauge pointer indicates compression or
combustion leakage i n t o the cooling system.
Because t h e vehicle i s equipped w i t h a catalytic
converter, do not remove spark plug wires or
short out cylinders to isolate t h e compression leak.
I f the needle on the d i a l of the pressure tester does
not fluctuate, race the engine a few times t o check
for a n a b n o r m a l a m o u n t of coolant or steam e m i t t i n g
from t h e exhaust pipe. Coolant or steam from the ex-
haust pipe may indicate a f a u l t y cylinder head gas-
ket, cracked engine cylinder block or cylinder head.
A convenient check for exhaust gas leakage i n t o
the cooling system i s provided b y a commercially
available " B l o c k Leak Check" tool. Follow manufac-
turers i n s t r u c t i o n s w h e n using t h i s product.
Combustion Leakage Test (without Pressure Tester)
D O N O T W A S T E reusable coolant. I f the solution
is clean a n d is being drained only to service the cool-
i n g system, d r a i n the coolant i n t o a clean container
for reuse.
WARNING:
DO
NOT
REMOVE THE CYLINDER
BLOCK DRAIN PLUGS OR LOOSEN THE RADIATOR
DRAINCOCK WITH THE SYSTEM HOT AND UNDER
PRESSURE
BECAUSE
SERIOUS
BURNS
FROM
COOLANT CAN OCCUR.
D r a i n sufficient coolant to allow thermostat r e -
moval. Refer to Thermostat Replacement. Disconnect
the w a t e r p u m p drive belt.
A d d coolant to the radiator to b r i n g the level t o
w i t h i n 6.3 m m (1/4 i n ) o f the top o f the thermostat
housing.
CAUTION: Avoid overheating. Do not operate the
engine for an excessive period of time. Open the
draincock immediately after the test to eliminate
boil over.
S t a r t
t h e engine
and accelerate
r a p i d l y t h r e e
times, t o approximately 3000 r p m w h i l e observing
the coolant. I f i n t e r n a l engine combustion gases axe
l e a k i n g i n t o the cooling system, bubbles w i l l appear
i n t h e coolant. I f bubbles do not appear, there i s no
i n t e r n a l combustion gas leakage.
COOLANT RESERVE SYSTEM (CRS)
The Coolant Reserve System (CRS) works i n con-
j u n c t i o n w i t h the radiator pressure cap t o u t i l i z e
t h e r m a l expansion and contraction of the coolant t o
keep t h e coolant free of trapped air. I t provides a vol-
ume for expansion and contraction, provides a conve-
n i e n t a n d safe method for checking coolant level a n d
adjusting level a t atmospheric pressure w i t h o u t re-
m o v i n g t h e radiator pressure cap. I t also provides
some reserve coolant to cover m i n o r leaks and evap-
oration or b o i l i n g losses (Fig. 8).
Fig. 8 Coolant Reserve System
Refer to "Coolant Level Check—Service",
"Deaera-
t i o n " , and "Radiator Pressure Cap" sections i n t h i s
group for CRS system operation and service. Vehicles
equipped w i t h a n electronic monitor system use a
level sensor i n the CRS t a n k , refer to Group 8, Elec-
t r i c a l , for service.
Should t h e CRS t a n k become coated w i t h corrosion
or emulsifiable o i l i t can be cleaned w i t h detergent
and water. Rinse the t a n k thoroughly before r e f i l l i n g
the cooling system as described i n the "Coolant" sec-
t i o n of t h i s group.
Advertisement
Table of Contents
