radiator cap CHEVROLET DYNASTY 1993 Service Manual

ENGINE COOLING SYSTEM
WARNINGS AND PRECAUTIONS
WARNING: ANTIFREEZE IS AN ETHYLENE GLYCOL
BASE COOLANT AND IS HARMFUL IF SWAL-
LOWED OR INHALED. IF SWALLOWED, DRINK
TWO GLASSES OF WATER AND INDUCE VOMIT-
ING. IF INHALED, MOVE TO FRESH AIR AREA.
SEEK MEDICAL ATTENTION IMMEDIATELY. DO
NOT STORE IN OPEN OR UNMARKED CONTAIN-
ERS. WASH SKIN AND CLOTHING THOROUGHLY
AFTER COMING IN CONTACT WITH ETHYLENE
GLYCOL. KEEP OUT OF REACH OF CHILDREN. DISPOSE OF GLYCOL BASE COOLANT PROP-
ERLY, CONTACT YOUR DEALER OR GOVERNMENT
AGENCY FOR LOCATION OF COLLECTION CEN-
TER IN YOUR AREA. DO NOT OPEN A COOLING SYSTEM WHEN THE
ENGINE IS AT RUNNING TEMPERATURE, PER-
SONAL INJURY CAN RESULT. AVOID RADIATOR COOLING FAN WHEN ENGINE
COMPARTMENT RELATED SERVICE IS PER-
FORMED, PERSONAL INJURY CAN RESULT.
CAUTION: Do not use straight antifreeze as engine
coolant, inadequate engine running temperatures
can result. Do not operate vehicle without proper concentra-
tion of recommended ethylene glycol coolant, high
running temperatures and cooling system corrosion
can result.
The engine cooling system will develop internal
pressure of 97 to 123 kPa (14 to 18 psi) at normal op-
erating temperature. Allow the vehicle approxi-
mately one half hour to cool off before opening the
cooling system. As an indicator of pressure, squeeze
the upper radiator hose between index finger and
thumb. If it collapses with little effort the system
would have low internal pressure and should be safe
to open to the first safety notch of the radiator cap.
Refer to Group 7, Cooling System.
COOLING SYSTEM INSPECTION
Coolant level (Fig. 5) should be inspected when
other engine compartment service is performed or
when coolant leak is suspected. Coolant recovery
tank level should read between the MIN and MAX
marks, located on the side of recovery tank, when the
engine is at normal operating temperature. Normal
coolant level maintenance does not require the re-
moval of radiator cap. Cooling system freeze protec-
tion should be tested at the onset of the winter
season or every 12 months. Service is required if
coolant is low, contaminated, rusty or freeze protec-
tion is inadequate. To properly test cooling system,
see Group 7, Cooling System.
The cooling system factory fill is a mixture of 50%
Glycol based antifreeze and 50% water. Using a suit-
able hydrometer, measure antifreeze concentration in
the radiator when the engine is cool. If the cooling
system has recently been serviced, allow coolant to
circulate for at least 20 minutes before taking hy-
drometer reading. Properly mixed coolant will pro-
tect the cooling system to -37ÉC (-35ÉF). If the freeze
protection is above -28ÉC (-20ÉF), drain enough cool-
ant from the cooling system to allow room to add an-
Fig. 3 Remove Oil Filter
Fig. 4 Install Oil Filter
Fig. 5 Coolant Recovery Tank
0 - 10 LUBRICATION AND MAINTENANCE Ä

tifreeze to achieve adequate protection. A mix table
on the coolant container indicates the amount of an-
tifreeze required to winterize the cooling system
based on the capacity, see Capacity Chart in General
Information section of this group.
SELECTING ANTIFREEZE
Chrysler Corporation recommends Mopar Anti-
freeze/Summer Coolant, or equivalent be used to win-
terize and protect cooling system.
RADIATOR CAP
The radiator cap must be secure to provide proper
pressure release and coolant recovery. Inspect and
test radiator cap when cooling system service is per-
formed or when problem is suspected.
COOLING SYSTEM SERVICE
The cooling system should be drained, flushed and
filled with the proper coolant mixture at the inter-
vals described in the Lubrication and Maintenance
Schedules. Refer to General Information section of
this group. For proper service instructions see Group
7, Cooling System.
ENGINE AIR CLEANER
The engine air cleaner should be serviced at the in-
tervals described in the Lubrication and Mainte-
nance Schedules. Refer to General Information
section of this group. Additional information can be
found in Group 14, Fuel System and Group 25, Emis-
sion System. Inspect all air cleaner hoses or tubes for
damage or leaks when other engine compartment
service is performed. Replace faulty components.
AIR CLEANER SERVICE
CAUTION: The air cleaner cover must be installed
properly for the emissions system and engine con-
troller to function correctly. Do not immerse paper air filter element or temper-
ature sensor in cleaning solvents, damage can re-
sult.
TO SERVICE AIR CLEANER ASSEMBLY: (1) Raise hood of vehicle and inspect all air cleaner
components for damage or improper attachment. (2) Remove air cleaner cover (Fig. 6, 7, 8, 9, or 10).
(3) Remove paper air filter element from air
cleaner body. Hold a shop light on throttle body side
of element. Inspect air intake side of element. If light
is visible through element, blow dust from element
(Fig. 11) and reuse. If element is saturated with oil
or light is not visible, replace filter. If element is sat-
urated with oil, perform crankcase ventilation sys-
tem tests. (4) Remove fiber crankcase filter (Fig. 6, 7, 8, 9, or
10) and clean with solvent, squeeze filter dry and ap- ply small amount of engine oil. If a metallic mesh is
used to retain fiber filter, clean mesh with solvent
and reuse.
(5) Clean inside of air cleaner cover and body with
vacuum or compressed air. If oily, wash with solvent. To Install, reverse the preceding operation.
Fig. 6 Air CleanerÐ3.0L Engine
Fig. 7 Air CleanerÐFlexible Fuel Engine
Fig. 8 Air CleanerÐ16 Valve Engine
Ä LUBRICATION AND MAINTENANCE 0 - 11

COOLING SYSTEM
CONTENTS
page page
ACCESSORY DRIVE BELTS ............... 24
ENGINE BLOCK HEATER ................. 28
GENERAL INFORMATION .................. 1 SERVICE PROCEDURES
.................. 10
SPECIFICATIONS ....................... 29
GENERAL INFORMATION
Throughout this group, references may be made to
a particular vehicle by letter or number designation.
A chart showing the breakdown of these designations
is included in the Introduction Section at the front of
this service manual.
COOLING SYSTEM
The cooling system consists of an engine cooling
module, thermostat, coolant, a water pump to circu-
late the coolant. The engine cooling module may con-
sist of a radiator, electric fan motor, shroud, radiator
pressure cap, coolant reserve system, transmission oil
cooler, hoses, clamps, air condition condenser, trans-
mission oil lines and charge air cooler.
² When Engine is cold: Thermostat is closed, cooling
system has no flow through the radiator. The coolant
bypass flows through the engine only. ²
When Engine is warm: Thermostat is open, cooling
system has bypass flow and coolant flow through ra-
diator. Its primary purpose is to maintain engine temper-
ature in a range that will provide satisfactory engine
performance and emission levels under all expected
driving conditions. It also provides hot water (cool-
ant) for heater performance and cooling for auto-
matic transmission oil. It does this by transferring
heat from engine metal to coolant, moving this
heated coolant to the radiator, and then transferring
this heat to the ambient air. Coolant flow circuits for 2.2L and 2.5L engine
equipped vehicles are shown in (Fig 1). Turbocharged
equipped engines coolant routing and plumbing are
shown in (Fig 2). The 3.0L engine coolant routing is
shown in (Fig 3). The 3.3L and 3.8L engine coolant
routing is shown in (Fig 5).
Fig. 1 Cooling System OperationÐ2.2/2.5L Engines
Ä COOLING SYSTEM 7 - 1

SERVICE PROCEDURES INDEX
page page
Automatic Transmission Oil Coolers .......... 23
Coolant ................................ 14
Coolant Recovery System (CRS) ............. 17
Cooling System Drain, Clean, Flush and Refill . . 15
Electric Fan Motor ........................ 22
Engine Thermostats ....................... 13
Fan Shroud ............................. 23 Fans
.................................. 21
Radiator Hoses .......................... 21
Radiator Pressure Cap .................... 18
Radiators ............................... 18
Testing System for Leaks .................. 17
Water Pumps ........................... 10
WATER PUMPS
A quick test to tell whether or not the pump is
working is to see if the heater warms properly. A
defective pump will not be able to circulate heated
coolant through the long heater hose. The water pump on all models can be replaced
without discharging the air conditioning system.
WATER PUMPÐ2.2/2.5L ENGINE
The 2.2/2.5L engine water pump has a diecast alu-
minum body and housing with a stamped steel impel-
ler. The 2.2/2.5L pump uses an O-ring gasket between
body and housing. The assembly bolts directly to the
block. Cylinder block to water pump sealing is provided
by a rubber O-ring.
REMOVAL (1) Drain cooling system. Refer to Draining Cooling
System in this group. (2) If equipped with air conditioning, see Solid
Mount Accessory Bracket in (Standard Service Proce-
dures) Group 9, Engine: (a) Remove air conditioning compressor and gen-
erator from solid mount bracket and set aside.It is
not necessary to discharge the a/c system. (b) Remove solid mount bracket.
(3) If the vehicle is not equipped with air condi-
tioning, remove generator and mounting bracket. (4) Disconnect lower radiator and heater hoses
from pump. (5) Remove water pump attaching screws to engine
(Fig. 1). Turbo III has a spacer between the water
pump and block on the lower screw.
DISASSEMBLY (1) Remove three screws holding pulley to water
pump. (2) Remove nine screws holding water pump body
to housing. Remove the pump body from housing
(Fig. 2). (3) Clean gasket surfaces on water pump housing
and engine block. (4) Remove and discard O-ring gaskets and clean
O-ring grooves.
Fig. 2 Water Pump ComponentsÐ2.2/2.5L
Fig. 1 Water PumpÐ2.2/2.5L Engines
7 - 10 COOLING SYSTEM Ä

INSTALLATIONÐ3.3L AND 3.8L ENGINE
Place a new gasket (dipped in water) on the water
box surface, center thermostat into opening in the in-
take manifold. Place housing over gasket and ther-
mostat, making sure thermostat is in recess provided
(Fig. 13). Bolt housing to intake manifold, tighten
bolts to 28 N Im (250 in. lbs.). Refill cooling system
(see Refilling System ).
COOLANT
The cooling system is designed around the coolant.
The coolant must accept heat from engine metal, in
the cylinder head area near the exhaust valves. Then
carry this heat to the radiator where the tube/fin as-
semblies of these components can give it up to the
air.
PERFORMANCE
Performance is measurable. For heat transfer pure
water excels (Formul a = 1 btu per minute for each
degree of temperature rise for each pound of water).
This formula is altered when necessary additives to
control boiling, freezing, and corrosion are added as
follows:
² Pure Water (1 btu) boils at 100ÉC (212ÉF) and
freezes at 0ÉC (32ÉF).
² 100 Percent Glycol (.7 btu) can cause a hot engine
and detonation and will raise the freeze point to 22ÉC
(-8ÉF).
² 50/50 Glycol and Water (.82 btu) is the recom-
mended combination that provides a freeze point of
-37ÉC(-35ÉF).The radiator, water pump, engine water
jacket, radiator pressure cap, thermostat, tempera-
ture gauge, sending unit and heater are all designed
for 50/50 glycol. Where required, a 56 percent glycol and 44 percent
water mixture will provide a freeze point of-59ÉC
(-50ÉF).
CAUTION: Richer mixtures cannot be measured
with field equipment which can lead to problems
associated with 100 percent glycol.
SELECTION AND ADDITIVES
The use of aluminum cylinder heads, intake mani-
folds, and water pumps requires special corrosion
protection. Mopar Antifreeze, Prestone II, Peak or
antifreeze containing Alugard 340-2, or their equiva-
lent are recommended for best engine cooling with-
out corrosion. When mixed only to a freeze point of
Fig. 11 Thermostat, Housing, and Water BoxÐ3.0L Engine
Fig. 12 Thermostat InstalledÐ3.0L Engine
Fig. 13 Thermostat, Housing and WaterboxÐ3.3Land 3.8L Engine
7 - 14 COOLING SYSTEM Ä

-37ÉC (-35ÉF) to -59ÉC (-50ÉF). If it looses color or
becomes contaminated, drain, flush, and replace with
fresh properly mixed solution.
SERVICE
Coolant should be changed at 52,500 miles or three
years, whichever occurs first, then every two years or
30,000 miles.
ROUTINE LEVEL CHECK
Do not remove radiator cap for routine coolant
level inspections. The coolant reserve system provides a quick visual
method for determining the coolant level without re-
moving the radiator cap. Simply observe, with the
engine idling and warmed up to normal operating
temperature, that the level of the coolant in the reserve
tank (Figs. 5 and 6) is between the minimum and
maximum marks.
ADDING ADDITIONAL COOLANT
The radiator cap should not be removed. When
additional coolant is needed to maintain this level, it
should be added to the coolant reserve tank. Use only
50/50 concentration of ethylene glycol type antifreeze
and water.
SERVICE COOLANT LEVEL
The cooling system is closed and designed to main-
tain coolant level to the top of the radiator. When servicing requires a coolant level check in the
radiator, the engine must be offand notunder pres-
sure. Drain several ounces of coolant from the radiator
drain cock while observing the Coolant Recovery Sys-
tem (CRS) Tank. Coolant level in the CRS tank should
drop slightly. Then remove the radiator cap. The radia-
tor should be full to the top. If not, and the coolant level
in the CRS tank is at the MIN mark there is a air leak
in the CRS system. Check hose or hose connections to
the CRS tank, radiator filler neck or the pressure cap
seal to the radiator filler neck for leaks.
LOW COOLANT LEVEL AERATION
Low coolant level in a cross flow radiator will equal-
ize in both tanks with engine off. With engine at
running operating temperature the high pressure inlet
tank runs full and the low pressure outlet tank drops.
If this level drops below the top of the transmission oil
cooler, air will be sucked into the water pump:
² Transmission oil will become hotter.
² High reading shown on the temperature gauge.
² Air in the coolant will also cause loss of flow through
the heater.
² Exhaust gas leaks into the coolant can also cause the
same problems.
DEAERATION
Air can only be removed from the system by gather-
ing under the pressure cap. On the next heat up it will
be pushed past the pressure cap into the CRS tank by
thermal expansion of the coolant. It then escapes to the
atmosphere in the CRS tank and is replaced with solid
coolant on cool down.
COOLING SYSTEM DRAIN, CLEAN, FLUSH AND
REFILL
Drain, flush, and fill the cooling system at the
mileage or time intervals specified in the Maintenance
Schedule in this Group. If the solution is dirty or rusty
or contains a considerable amount of sediment, clean
and flush with a reliable cooling system cleaner. Care
should be taken in disposing of the used engine coolant
from your vehicle. Check governmental regulations for
disposal of used engine coolant.
DRAINING
To drain cooling system move temperature selector
for heater to full heat with engine running (to provide
vacuum for actuation). Without removing radiator
pressure cap and with system not under pres-
sure, Shut engine off and open draincock. The coolant
reserve tank (Fig. 5) should empty first, then remove
radiator pressure cap. (if not, see Testing Cooling
System for leaks). To vent 2.2/2.5L engines remove the
plug above thermostat housing (Fig. 1). For Turbo III
engines remove coolant temperature sensor in the
thermostat housing (Fig. 2). For 3.3L /3.8L engine
remove the engine temperature sending unit (Fig. 3).
Removal of a plug or other component is required
because the thermostat has no air vent and prevents
air flow through it. This allows the coolant to drain
from the engine block.
Fig. 1 Thermostat Housing Drain/Fill PlugÐ2.2/2.5L Engines
Ä COOLING SYSTEM 7 - 15

CLEANING
Drain cooling system (see: Draining Cooling Sys-
tem ) and refill with clean water (see: Refilling
Cooling System ). Run engine with radiator cap in-
stalled until upper radiator hose is hot. Stop engine
and drain water from system. If water is dirty, fill,
run and drain system again until water runs clear.
REVERSE FLUSHING
Reverse flushing of the cooling system is the forc-
ing of water through the cooling system, using air
pressure in a direction opposite to that of the normal
flow of water. This is only necessary with dirty sys-
tems and evidence of partial plugging.
RADIATOR Drain cooling system and remove radiator hoses
from engine. Install suitable flushing gun in radiator
lower hose. Fill radiator with clean water and turn
on air in short blasts. CAUTION: Internal radiator pressure must not ex-
ceed 138 kPa (20 psi) as damage to radiator may re-
sult. Continue this procedure until water runs clear.
ENGINE
Drain radiator (see: Draining Cooling System )
and remove hoses from radiator. Remove engine
thermostat and reinstall thermostat housing. Install
suitable flushing gun to thermostat housing hose.
Turn on water, and when engine is filled, turn on
air, but no higher than 138 kPa (20 psi) in short
blasts. Allow engine to fill between blasts of air.
Continue this procedure until water runs clean. In-
stall thermostat using a new housing gasket. Fill
cooling system (See Refilling Cooling System ).
CHEMICAL CLEANING
One type of corrosion encountered with aluminum
cylinder heads is aluminum hydroxide deposits. Cor-
rosion products are carried to the radiator and depos-
ited when cooled off. They appear as dark grey when
wet and white when dry. This corrosion can be re-
moved with a two part cleaner (oxalic acid and neu-
tralizer) available in auto parts outlets. Follow
manufacturers directions for use.
REFILLING
First clean system to remove old glycol, see Cooling
System Cleaning. Fill system using antifreeze described in Coolant
section. Fill 50 percent of capacity with 100 percent
glycol. Then complete filling system with water. The
2.2/2.5L engines require venting by removal of the
plug on top of the water box (Fig. 1). Turbo III en-
gines require venting by removing the coolant tem-
perature sensor on top of the thermostat housing
(Fig. 2). The 3.3/3.8L Engines require removal of the
Engine Temperature Sending Unit on the front of
the cylinder head (Fig. 3). The thermostat in these
engines do not allow air flow through them. When
coolant reaches the vent holes;
² Install vent plug and tighten to 20 N Im (15 ft. lbs.)
for 2.2/2.5L Engines.
² Install Coolant Temperature Sensor and tighten to
27 N Im (20 ft. lbs.) for Turbo III Engine.
² Install Engine Temperature Sending Unit and
tighten to 7 N Im (60 in. lbs.) for 3.3/3.8L Engines.
Continue filling system until full, this provides bet-
ter heater performance. Be careful not to spill
coolant on drive belts or the generator. Fill coolant reserve system to at least the MAX
mark with 50/50 solution. It may be necessary to add
coolant to the reserve tank to maintain coolant level
between the MAX and MIN mark after three or four
warm-up, cool down cycles and trapped air has been
removed.
Fig. 2 Coolant Temperature SensorÐTurbo III Drain/Fill
Fig. 3 Engine Temperature Sending UnitÐ3.3L and 3.8L Drain/Fill
7 - 16 COOLING SYSTEM Ä

TESTING SYSTEM FOR LEAKS
With engine not running, wipe the radiator filler
neck sealing seat clean. The radiator should be full. Attach a radiator pressure tester to the radiator, as
shown in (Fig. 4) and apply 104 kPa (15 psi) pres-
sure. If the pressure drops more than 2 psi in 2 min-
utes inspect all points for external leaks. All hoses, radiator and heater, should be moved
while at 15 psi since some leaks occur while driving
due to engine rock, etc.
If there are no external leaks after the gauge dial
shows a drop in pressure, detach the tester. Start en-
gine and run the engine to normal operating temper-
ature in order to open the thermostat and allow the
coolant to expand. Re-attach the tester. If the needle
on the dial fluctuates it indicates a combustion leak,
usually a head gasket leak.
WARNING: WITH TOOL IN PLACE PRESSURE
BUILDS UP FAST. ANY EXCESSIVE AMOUNT OF
PRESSURE BUILT UP BY CONTINUOUS ENGINE
OPERATION MUST BE RELEASED TO A SAFE
PRESSURE POINT. NEVER PERMIT PRESSURE TO
EXCEED 138 KPA (20 PSI).
If the needle on the dial does not fluctuate, race
the engine a few times. If an abnormal amount of
coolant or steam is emitted from the tail pipe, it may
indicate a faulty head gasket, cracked engine block
or cylinder head. There may be internal leaks which can be deter-
mined by removing the oil dip-stick. If water glob-
ules appear intermixed with the oil it will indicate a internal leak in the engine. If there is an internal
leak, the engine must be disassembled for repair.
COOLANT RECOVERY SYSTEM (CRS)
This system works in conjunction with the radiator
pressure cap to utilize thermal expansion and con-
traction of the coolant to keep the coolant free of
trapped air. It provides a volume for expansion and
contraction, provides a convenient and safe method
for checking coolant level and adjusting level at at-
mospheric pressure without removing the radiator
pressure cap. It also provides some reserve coolant to
cover minor leaks and evaporation or boiling losses.
All vehicles are equipped with this system (Figs. 5
and 6).
See Coolant Level Check Service, Deaeration and
Pressure Cap sections for operation and service. Ve-
hicles equipped with the electric monitor system use
a level sensor in the CRS tank, see Group 8E Elec-
trical for service.
Fig. 4 Pressure Testing Cooling System
Fig. 5 Coolant Recovery System Typical
Fig. 6 Coolant Recovery SystemÐAC-AY Models
Ä COOLING SYSTEM 7 - 17

RADIATOR PRESSURE CAP
Radiators are equipped with a pressure cap which
releases pressure at some point within a range of
97-124 kPa (14-18 psi) (Fig. 7). The system will operate at higher than atmospheric
pressure which raises the coolant boiling point allow-
ing increased radiator cooling capacity. There is also a vent valve in the center of the cap that
allows a small coolant flow to the CRS tank. If valve is
stuck shut, the radiator hoses will be collapsed
on cool down. Clean the vent valve (Fig. 7) to
ensure proper sealing when boiling point is
reached.
There is also a gasket in the cap to seal to the top of
the filler neck so that vacuum can be maintained for
drawing coolant back into the radiator from the coolant
reserve system tank.
RADIATOR CAP TO FILLER NECK SEAL PRES- SURE RELIEF CHECK
The pressure cap upper gasket (seal) pressure relief
can be checked by removing the overflow hose at the
radiator filler neck nipple (Fig. 7). Attach the Radiator
Pressure Tool to the filler neck nipple and pump air
into the radiator. Pressure cap upper gasket should
relieve at 69-124 kPa (10-18 psi) and hold pressure at
55 kPa (8 psi) minimum.
WARNING: THE WARNING WORDS DO NOT OPEN
HOT ON THE RADIATOR PRESSURE CAP IS A
SAFETY PRECAUTION. WHEN HOT, PRESSURE
BUILDS UP IN COOLING SYSTEM. TO PREVENT
SCALDING OR INJURY, THE RADIATOR CAP
SHOULD NOT BE REMOVED WHILE THE SYSTEM IS
HOT AND/OR UNDER PRESSURE.
There is no need to remove the radiator cap at any
time except for the following purposes:
(1) Check and adjust antifreeze freeze point.
(2) Refill system with new antifreeze.
(3) Conducting service procedures.
(4) Checking for vacuum leaks.
WARNING: IF VEHICLE HAS BEEN RUN RECENTLY,
WAIT 15 MINUTES BEFORE REMOVING CAP. THEN PLACE A SHOP TOWEL OVER THE CAP AND WITH-
OUT PUSHING DOWN ROTATE IT COUNTER-
CLOCKWISE TO THE FIRST STOP. ALLOW FLUIDS
TO ESCAPE THROUGH THE OVERFLOW TUBE AND
WHEN THE SYSTEM STOPS PUSHING COOLANT
AND STEAM INTO THE CRS TANK AND PRESSURE
DROPS PUSH DOWN AND REMOVE THE CAP COM-
PLETELY. SQUEEZING THE RADIATOR INLET HOSE
WITH A SHOP TOWEL (TO CHECK PRESSURE) BE-
FORE AND AFTER TURNING TO THE FIRST STOP IS
RECOMMENDED.
PRESSURE TESTING RADIATOR CAPS
Dip the pressure cap in water, clean any deposits off
the vent valve or its seat and apply cap to end of
Radiator Pressure Tool. Working the plunger, bring the
pressure to 104 kPa (15 psi) on the gauge. If the
pressure cap fails to hold pressure of at least 97 kPa
(14 psi) replace cap. See CAUTION
If the pressure cap tests properly while positioned on
Radiator Pressure Tool, but will not hold pressure or
vacuum when positioned on the radiator. Inspect the
radiator filler neck and cap top gasket for irregularities
that may prevent the cap from sealing properly.
CAUTION: Radiator Pressure Tool is very sensitive to
small air leaks which will not cause cooling system
problems. A pressure cap that does not have a
history of coolant loss should not be replaced just
because it leaks slowly when tested with this tool.
Add water to the tool. Turn tool upside down and
recheck pressure cap to confirm that cap is bad.
INSPECTION
Hold the cap in hand, right side up(Fig. 7). The
vent valve at the bottom of the cap should open. If the
rubber gasket has swollen and prevents the valve from
opening, replace the cap. Hold the cleaned cap in hand upside down.If any
light can be seen between vent valve and rubber
gasket, replace cap. Do not use a replacement cap
that has a spring to hold the vent shut. Replacement cap must be of the type designed for
coolant reserve systems. This design assures coolant
return to radiator.
RADIATORS
The radiators are crossflow types (horizontal tubes)
with design features that provide greater strength as
well as sufficient heat transfer capabilities to keep the
engine satisfactorily cooled.
CAUTION: Plastic tanks, while stronger then brass
are subject to damage by impact, such as wrenches.
Fig. 7 Radiator Pressure Cap Filler Neck
7 - 18 COOLING SYSTEM Ä

RADIATOR DRAINCOCK SERVICE
REMOVAL (1) Turn the drain cock stem counterclockwise to
unscrew the stem. When the stem is unscrewed to
the end of the threads, pull the stem (Fig. 10) from
the radiator tank.
INSTALLATION (1) Push the draincock assembly body into the
tank opening until it snaps into place. (2) Tighten the draincock stem by turning clock-
wise to 2.0-2.7 N Im (18-25 in. lbs.) torque.
RADIATOR COOLANT FLOW CHECK
To determine whether coolant is flowing through
the cooling system, use the following procedure: (1) If engine is cold, idle engine until normal oper-
ating temperature is reached. Then feel the upper ra-
diator hose. If it is hot, coolant is circulating.
WARNING: DO NOT REMOVE RADIATOR PRES-
SURE CAP WITH THE SYSTEM HOT AND UNDER
PRESSURE BECAUSE SERIOUS BURNS FROM
COOLANT CAN OCCUR.
Fig. 9 Cooling ModuleÐTypical
Fig. 8 Pressure Testing Radiator Cap
Fig. 10 Draincock AssemblyÐTypical
Ä COOLING SYSTEM 7 - 19