check engine CHRYSLER VOYAGER 1996 Owner's Manual

DESCRIPTION AND OPERATION
CLUTCH RELEASE SYSTEM
CLUTCH CABLE Ð LHD
The manual transaxle clutch release system has a
unique self-adjusting mechanism to compensate for
clutch disc wear (Fig. 7). This adjuster mechanism is
located within the clutch cable assembly. The preload
spring maintains tension on the cable. This tension
keeps the clutch release bearing continuously loaded
against the fingers of the clutch cover assembly.
HYDRAULIC CLUTCH Ð RHD
Leverage, clamping force, and friction are what
make the clutch work. The disc serves as the friction
element and a diaphragm spring and pressure plate
provide the clamping force. The clutch pedal, hydrau-
lic linkage, release lever and bearing provide the
leverage to disengage and engage the modular clutch
assembly.
The modular clutch assembly contains the cover,
diaphragm spring, pressure plate, disc and flywheel
in one unit. The modular clutch also uses a drive
plate and is bolted to and driven by the drive plate.
The clutch linkage uses hydraulic pressure to oper-
ate the clutch. The clutch master cylinder push rod is
connected to the clutch pedal and the slave cylinder
push rod is connected to the release lever in the
clutch housing.
Depressing the clutch pedal develops fluid pressure
in the clutch master cylinder. This pressure is trans-
mitted to the slave cylinder through a connecting
line. In turn, the slave cylinder operates the clutch
release lever.
The clutch release bearing is mounted on the
transmission front bearing retainer. The bearing is
attached to the release lever, which moves the bear-
ing into contact with the clutch cover diaphragm
spring.Slave cylinder force causes the release lever to
move the release bearing into contact with the dia-
phragm spring. As additional force is applied, the
bearing presses the diaphragm spring fingers inward
on the fulcrums. This action moves the pressure
plate rearward relieving clamp force on the disc. The
clutch disc is disengaged and not driven at this point.
The process of clutch engagement is simply the
reverse of what occurs during disengagement. Releas-
ing pedal pressure removes clutch linkage pressure.
The release bearing moves away from the diaphragm
spring which allows the pressure plate to exert
clamping force on the clutch disc.
CLUTCH PEDAL POSITION SWITCH
The clutch pedal position switch functions as a
safety interlock device. It prevents possible engine
cranking with the clutch engaged.
The clutch pedal position switch is wired in series
between the starter relay coil and the ignition
switch.
The clutch pedal position switch is mounted to a
bracket located behind the clutch pedal. The switch
is held in place by four plastic wing tabs.
The clutch pedal position switch IS NOT adjust-
able. The pedal blade contacts the switch in the down
position (Fig. 8).
DIAGNOSIS AND TESTING
CLUTCH PEDAL POSITION SWITCH
CLUTCH PEDAL POSITION
SWITCH±ELECTRICAL TEST
Disconnect clutch pedal position switch harness
from instrument panel wiring harness. Using an
ohmmeter, check for continuity between the two ter-
minals in the connector on the switch harness. There
should be no continuity between the terminals when
Fig. 7 Clutch Cable Ð LHD
Fig. 8 Clutch Pedal Position Switch and
Components Ð LHD Shown
6 - 4 CLUTCHNS/GS

the switch is in its normal (fully extended) position.
When the switch is depressed more than 1.25 mm
(0.050), the ohmmeter should show continuity (zero
ohms).
If ohmmeter readings do not fall within these
ranges, the switch is defective, and must be replaced.
CLUTCH PEDAL POSITION
SWITCH±MECHANICAL TEST
With the park brake set and the vehicleIN NEU-
TRAL,turn the key to the start position. The vehicle
should not crank. If the vehicle cranks, the switch is
defective (shorted out) and must be replaced. If the
vehicle does not crank proceed to the next step.
WARNING: BEFORE PERFORMING THIS STEP, BE
SURE THAT THE AREA IN FRONT OF THE VEHICLE
IS CLEAR OF OBSTRUCTIONS AND PEOPLE. VEHI-
CLE MAY MOVE WHEN PERFORMING THIS TEST.With the park brake set and the vehicleIN GEAR,
turn the key to the start position and hold it there.
Slowly depress the clutch pedal and feel for any
vehicle motion when the starter is energized. If there
is no motion the switch is working properly.
If motion is felt, check to see if the switch is mak-
ing contact when the pedal is between 25 mm (1.0
in.) and 6 mm (0.25 in.) from the floor. If this condi-
tion is met, then the problem is either the clutch or
the clutch actuation system (See ªClutch Will Not
Disengage Properlyº). If this condition is not met,
then the switch mounting tab on the brake bracket is
bent, and the brake bracket must be replaced.
If vehicle will not crank, even with clutch pedal
pressed to the floor, refer to ªService Diagnosis-
Clutch Pedal Position Switchº chart in this section.
SERVICE DIAGNOSIS±CLUTCH PEDAL POSITION SWITCH
CONDITION POSSIBLE CAUSES CORRECTION
ENGINE WON'T CRANK WHEN
CLUTCH PEDAL IS PRESSED TO
THE FLOORSwitch does not have continuity
when plunger is depressed 1.25 mmDefective switch. Replace switch.
Switch plunger is not depressed
when clutch pedal is pushed to the
floorFloor mat interferes with clutch pedal
movement. Move floor mat out of the
way.
Switch mounting bracket is bent.
Replace brake bracket assembly
Problem is related to other
components in the starting circuitCheck other components in the
starting circuit. Refer to Section 8A,
Battery/Starting/Charging System.
NS/GSCLUTCH 6 - 5
DIAGNOSIS AND TESTING (Continued)

CLUTCH DIAGNOSIS
Problem diagnosis will generally require a road
test to determine the type of fault. Component
inspection will then determine the problem after road
testing.
Drive the vehicle at normal speeds during road
test. Shift the transaxle through all gear ranges andobserve clutch action. If chatter, grab, slip, or
improper release is experienced, remove and inspect
the clutch components. If the problem is noise or
hard shifting, further diagnosis may be needed. The
transaxle or other driveline components may actually
be at fault.
SERVICE DIAGNOSIS±CLUTCH GRAB/CHATTER
CONDITION POSSIBLE CAUSES CORRECTION
CLUTCH DISC FACING
COVERED WITH OIL OR
GREASEOil leak at engine rear main or transaxle
input shaft sealCorrect leak and replace clutch assembly
NO FAULT FOUND WITH
CLUTCH
COMPONENTSProblem actually related to suspension
or driveline componentFurther diagnosis required. Check
engine/transmission mounts, suspension
attaching parts and other driveline
components as needed.
Engine related problems Check EFI and ignition systems
PARTIAL ENGAGEMENT
OF CLUTCH DISCClutch cover, spring, or release fingers
bent, distorted (rough handling, improper
assembly)Replace clutch assembly
Clutch disc damaged or distorted Replace clutch assembly
Clutch misalignment Check alignment and runout of flywheel,
disc, or cover. Check clutch housing to
engine dowels and dowel holes for
damage. Correct as necessary.
SERVICE DIAGNOSIS±CLUTCH SLIPS
CONDITION POSSIBLE CAUSES CORRECTION
DISC FACING WORN
OUTNormal wear. Replace clutch assembly.
Driver frequently rides (slips) clutch,
results in rapid wear overheating.Replace clutch assembly
Insufficient clutch cover diaphragm
spring tensionReplace clutch assembly
CLUTCH DISC FACING
CONTAMINATED WITH
OIL OR GREASELeak at rear main oil seal or transaxle
input shaft sealReplace leaking seals. Replace clutch
assembly.
Road splash, water entering housing Seal housing. Inspect clutch assembly.
CLUTCH IS RUNNING
PARTIALLY
DISENGAGEDRelease bearing sticking or binding,
does not return to normal running
position.Verify that bearing is actually binding.
Then, replace bearing and transmission
front bearing retainer if sleeve surface is
damaged.
Cable self-adjuster mechanism sticking
or binding causing high preload (LHD
Applications only)Verify that self-adjuster is free to move
(LHD Applications only)
CLUTCH DISC FACINGS
HAVE FRACTURED INTO
SMALL PIECESDriver performs a 5-1 downshift at
vehicle speed in excess of 60 miles per
hourAlert driver to problem cause. Replace
clutch assembly.
Excessive heat from slippage Replace clutch assembly
6 - 6 CLUTCHNS/GS
DIAGNOSIS AND TESTING (Continued)

CLUTCH COVER AND DISC RUNOUT
Check condition of the clutch cover before installa-
tion. A warped cover or diaphragm spring will cause
grab and/or incomplete release or engagement. Use
care when handling the clutch assembly. Impact can
distort the cover, diaphragm spring, and release fin-
gers.
CLUTCH CHATTER COMPLAINTS
For all clutch chatter complaints, do the following:
(1) Check for loose, misaligned, or broken engine
and transmission mounts. If present, they should be
corrected at this time. Test vehicle for chatter. If
chatter is gone, there is no need to go any further. If
chatter persists:
(2) Check to see if clutch cable routing is correct
and operates smoothly (LHD applications).
(3) Check for loose connections in drivetrain. Cor-
rect any problems and determine if clutch chatter
complaints have been satisfied. If not:
(4) Remove transaxle. See Group 21, Manual Tran-
saxle for procedure.
(5) Check to see if the release bearing is sticky or
binding. Replace bearing, if needed.
(6) Check linkage for excessive wear on the pivot
shaft, fork, and bushings. Replace all worn parts.
(7) Check clutch assembly for contamination (dirt,
oil). Replace clutch assembly, if required.
(8) Check to see if the clutch disc hub splines are
damaged. Replace with new clutch assembly, if nec-
essary.
(9) Check input shaft splines for damage. Replace,
if necessary.
(10) Check for uneven wear on clutch fingers.
(11) Check for broken clutch cover diaphragm
spring fingers. Replace with new clutch assembly, if
necessary.
CLASH±INTO±REVERSE COMPLAINTS
(1) Depress clutch pedal to floor and hold. After
three seconds, shift to reverse. If clash is present,
clutch has excessive spin time.
NOTE: Verify that nothing is obstructing pedal
travel. Floormats or other articles located under-
neath the clutch pedal could prevent the clutch
from disengaging fully.
(2) Remove transaxle. See Group 21, Manual Tran-
saxle for procedure.
(3) Check the input shaft spline, clutch disc
splines, and release bearing for dry rust. If present,
clean rust off and apply a light coat of bearing grease
to the input shaft splines. Apply grease on the input
shaft splines only where the clutch disc slides. Verify
that the clutch disc slides freely along the input shaft
spline.(4) Check to see if the clutch disc hub splines are
damaged, and replace with new clutch assembly if
required.
(5) Check the input shaft for damaged splines.
Replace as necessary.
(6) Check for broken clutch cover diaphragm
spring fingers.
(7) Install clutch assembly and transaxle.
REMOVAL AND INSTALLATION
CLUTCH CABLE SYSTEM Ð LHD
REMOVAL
(1) Hoist vehicle
(2) Using a pair of pliers, grasp end of clutch cable
and pull downward.
(3) Remove clutch cable retaining clip from clutch
release lever (Fig. 9).
(4) Guide cable through slot in transaxle and dis-
connect (Fig. 10).
(5) Unsnap cable from the cable guide located at
the left shock tower (Fig. 10).
(6) Inside the vehicle, remove the driver side lower
dash cover and steel support plate. This provides
access to the top of the clutch pedal.
(7) Disconnect clutch cable upstop/spacer with
cable strand from clutch pedal (Fig. 11) (Fig. 12).
Fig. 9 Clutch Cable Retaining Clip Ð LHD
6 - 8 CLUTCHNS/GS
DIAGNOSIS AND TESTING (Continued)

INSTALLATION
1. Position the slave cylinder assembly to the tran-
saxle deck and secure with the nut and washer
assemblies (2) and tighten to specifications (Fig. 14).
2. Make sure the slave cylinder pushrod is prop-
erly seated in the cup end of the clutch release lever.
3. Connect the quick connect coupling. Refer to the
ªQuick Connect Couplingº removal and installation
procedure in this section.
MODULAR CLUTCH ASSEMBLY (2.0L AND 2.4L
GASOLINE)
The transaxle must be removed to service the mod-
ular clutch assembly and components (Fig. 17). Refer
to Group 21 for the ªA-558 Manual Transaxleº
removal procedure.
CLUTCH ASSEMBLY (2.5L DIESEL)
The transaxle must be removed to service the
clutch disc assembly and components.
REMOVAL
(1) Remove the transaxle, refer to Group 21, Tran-
saxle.
(2) Install universal clutch alignment tool into the
clutch assembly (this will prevent the clutch from
inadvertently being dropped).
(3) To avoid distortion of the pressure plate,
remove the clutch pressure plate bolts a few turns at
a time. Use a crisscross pattern until all bolts are
loosened.
(4) Carefully remove the clutch pressure plate and
disc (Fig. 18).To service the flywheel, refer to Group 9, Engine.
INSPECTION
Inspect for oil leakage through engine rear main
bearing oil seal and transaxle input shaft seal. If
leakage is noted, it should be corrected at this time.
The friction faces of the flywheel and pressure
plate should not have:
²Excessive discoloration
²Burned areas
²Small cracks
²Deep grooves
²Ridges
Replace parts as required.
CAUTION: Do not polish flywheel to a mirror like
surface. Clean the flywheel face with medium sand-
paper (80-160 grade), then wipe the surface with
mineral spirits. If the surface is severely scored,
heat checked, or warped, replace the flywheel.
CAUTION: Do not flat-machine the flywheel face.
The surface profile is slightly tapered and has a
0.30 mm step.
The disc assembly should be handled without
touching the facings. Replace disc if the facings show
evidence of grease or oil soakage, or wear to within
less than .38 mm (.015 inch) of the rivet heads. The
splines on the disc hub and transaxle input shaft
should be a snug fit without signs of excessive wear.
Metallic portions of disc assembly should be dry and
clean, and not been discolored from excessive heat.
Each of the arched springs between the facings
should not be broken and all rivets should be tight.
Wipe the friction surface of the pressure plate with
mineral spirits.
Using a straight edge, check clutch cover (pressure
plate) for flatness. The clutch cover (pressure plate)
Fig. 17 Modular Clutch Assembly Ð 2.0L and 2.4L
Fig. 18 Clutch Disc, Cover and Pressure Plate
NS/GSCLUTCH 6 - 13
REMOVAL AND INSTALLATION (Continued)

ADJUSTMENTS
CLUTCH CABLE Ð LHD
The manual transaxle clutch release system has a
unique self-adjusting mechanism to compensate for
clutch disc wear. This adjuster mechanism is located
within the clutch cable assembly. The preload spring
maintains tension on the cable. This tension keeps
the clutch release bearing continuously loaded
against the fingers of the clutch cover assembly.
ADJUSTER MECHANISM FUNCTION CHECK Ð
LHD
(1) With slight pressure, pull the clutch release
lever end of the cable to draw the cable taut. Push
the clutch cable housing toward the dash panel (With
less than 20 lbs. of effort, the cable housing should
move 30-50mm.). This indicates proper adjuster
mechanism function. If the cable does not adjust,
determine if the mechanism is properly seated on the
bracket.
(2) If the adjust mechanism functions properly,
route cable to the transaxle.
(3) Insert cable into transaxle and through clutch
release lever. Ensure the cable is routed through the
smaller hole in the transaxle deck (Fig. 10).
(4) Pull down on cable and insert cable retaining
clip onto clutch cable end.
(5) Check clutch pedal position switch operation.
CLUTCH PEDAL POSITION SWITCH
The clutch pedal position switch is mounted to a
bracket located behind the clutch pedal. The switch
is held in place by four plastic wing tabs.
The clutch pedal position switch IS NOT adjust-
able. The pedal blade contacts the switch in the down
position.
SPECIFICATIONS
CLUTCH TIGHTENING REFERENCE
2.0/2.4 LITER GASOLINE ENGINE
DESCRIPTION TORQUE
Drive Plate Bolts............95N´m(70ft.lbs.)
Lower Trans. Cover.........12N´m(105 in. lbs.)
Modular Clutch Bolts.........74N´m(55ft.lbs.)
Upper Trans. Cover.........12N´m(105 in. lbs.)
2.5 LITER DIESEL ENGINE
DESCRIPTION TORQUE
Flywheel Bolts..............95N´m(70ft.lbs.)
Lower Trans. Cover.........12N´m(105 in. lbs.)
Clutch Pressure Plate Bolts....27N´m(20ft.lbs.)
Upper Trans. Cover.........12N´m(105 in. lbs.)
6 - 16 CLUTCHNS/GS

COOLING SYSTEM
CONTENTS
page page
GENERAL INFORMATION
ACCESSORY DRIVE BELTS................ 1
AUTOMATIC TRANSMISSION OIL COOLERÐ
2.4L................................. 3
COOLANT RECOVERY SYSTEM (CRS)....... 3
COOLANT.............................. 3
COOLING SYSTEM....................... 2
ENGINE BLOCK HEATER.................. 5
ENGINE THERMOSTAT.................... 3
RADIATOR PRESSURE CAP................ 4
RADIATOR............................. 3
WATER PUMPS......................... 3
DESCRIPTION AND OPERATION
COOLANT PERFORMANCE................. 6
RADIATOR HOSES AND CLAMPS........... 6
WATER PIPESÐ3.0L ENGINE.............. 6
WATER PUMPÐ3.3/3.8L ENGINES.......... 7
WATER PUMPÐ2.4L ENGINE.............. 6
WATER PUMPÐ3.0L ENGINE.............. 6
DIAGNOSIS AND TESTING
ACCESSORY DRIVE BELT.................. 7
COOLING SYSTEM DIAGNOSIS............. 8
DEAERATION.......................... 16
ELECTRIC FAN MOTOR TEST.............. 14
LOW COOLANT LEVEL AERATION.......... 15
PRESSURE TESTING RADIATOR CAP....... 15
RADIATOR CAP TO FILLER NECK SEAL
PRESSURE RELIEF CHECK.............. 15
RADIATOR COOLANT FLOW TEST.......... 14
RADIATOR FAN CONTROL................ 14
TEMPERATURE GAUGE INDICATION........ 16
TESTING COOLING SYSTEM FOR LEAKS.... 14
SERVICE PROCEDURES
COOLANT LEVEL CHECKÐROUTINE........ 16
COOLANT LEVEL SERVICE................ 16COOLANTÐADDING ADDITIONAL.......... 16
COOLING SYSTEMÐDRAINING............ 16
COOLING SYSTEMÐREFILLING........... 16
REMOVAL AND INSTALLATION
ACCESSORY DRIVE BELTSÐ2.4L.......... 23
ACCESSORY DRIVE BELTSÐ3.0L.......... 24
ACCESSORY DRIVE BELTÐ3.3/3.8L........ 24
ENGINE BLOCK HEATER................. 23
FAN MODULE.......................... 22
RADIATOR DRAINCOCK.................. 21
RADIATOR............................ 21
THERMOSTATÐ2.4L ENGINE............. 19
THERMOSTATÐ3.0L ENGINE............. 20
THERMOSTATÐ3.3/3.8L ENGINES......... 20
WATER PUMP INLET TUBEÐ2.4L ENGINE . . . 17
WATER PUMPÐ3.3/3.8L ENGINES......... 19
WATER PUMPÐ2.4L ENGINE............ 17
WATER PUMPÐ3.0L ENGINE............. 18
CLEANING AND INSPECTION
ACCESSORY DRIVE BELT................. 25
CHEMICAL CLEANING................... 25
COOLING SYSTEM CLEANING............. 25
RADIATOR PRESSURE CAP............... 25
REVERSE FLUSHING THE ENGINE......... 25
REVERSE FLUSHING THE RADIATOR....... 25
WATER PUMP......................... 24
ADJUSTMENTS
BELT TENSION CHART................... 26
BELT TENSION GAUGE METHOD........... 26
PROPER BELT TENSION................. 25
SPECIFICATIONS
COOLING SYSTEM CAPACITY............. 26
TORQUE CHART........................ 26
SPECIAL TOOLS
COOLING............................. 26
GENERAL INFORMATION
ACCESSORY DRIVE BELTS
The accessory drive system utilizes two different
style of drive belts. The conventional V-belt and the
Poly-V belt are used to drive the generator, air con-
ditioning compressor, power steering pump and waterpump. Satisfactory performance of these belts
depends on belt condition and proper belt tension.
Belt tensioning should be performed with the aid of a
Burroughs gauge Special Tool C-4162. Because of
space limitations in the engine compartment, the use
of the gauge may be restricted. Raise the vehicle on a
hoist and then remove the splash shield to gain
access to the drive belts.
NSCOOLING SYSTEM 7 - 1

COOLANT RECOVERY SYSTEM (CRS)
This system works with the radiator pressure cap
to use thermal expansion and contraction of the cool-
ant to keep the coolant free of trapped air. Provides a
convenient and safe method for checking coolant
level and adjusting level at atmospheric pressure
without removing the radiator pressure cap. It also
provides some reserve coolant to cover deaeration
and evaporation or boiling losses. All vehicles are
equipped with this system and take various shapes
and forms. (Fig. 3) shows a typical system in the typ-
ical location.
See Coolant Level Service, and Deaeration, and
Pressure Cap sections for operation and service.
AUTOMATIC TRANSMISSION OIL COOLERÐ2.4L
Oil cooler is internal oil to coolant type, mounted
in the radiator left tank (Fig. 4). Rubber oil lines feed
the oil cooler and the automatic transmission. Use
only approved transmission oil cooler hose. Since
these are molded to fit space available, molded hoses
are recommended.
ENGINE THERMOSTAT
The engine cooling thermostats are a wax pellet
driven, reverse poppet choke type. They are designed
to provide the fastest warm up possible by prevent-
ing leakage through them and to guarantee a mini-
mum engine operating temperature of 88 to 93ÉC
(192 to 199ÉF). They also automatically reach wide
open so they do not restrict flow to the radiator as
temperature of the coolant rises in hot weather to
around 104ÉC (220ÉF). Above this temperature the
coolant temperature is controlled by the fan, the
radiator, and the ambient temperature, not the ther-
mostat.
WATER PUMPS
A quick test to tell whether the pump is working is
to see if the heater warms properly. A defective pump
can not circulate heated coolant through the long
heater hose.The water pump on all models can
be replaced without discharging the air condi-
tioning 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. Cool-
ant then carries this heat to the radiator, where the
tube/fin assemblies of these components can give it
up to the air.
The use of aluminum cylinder heads, intake mani-
folds, and water pumps requires special corrosion
protection. MopartAntifreeze or the equivalent is
recommended for best engine cooling without corro-
sion, when mixed only to a freeze point of -37ÉC
(-35ÉF) to -59ÉC (-50ÉF). If it loses color or becomes
contaminated, drain, flush, and replace with fresh
properly mixed solution.
CAUTION: Do not use well water, or suspect water
supply in cooling system. A 50/50 ethylene glycol
and distilled water mix is recommended.
RADIATOR
The radiators are cross-flow types (horizontal
tubes) with design features that provide greater
strength along with sufficient heat transfer capabili-
Fig. 3 Coolant Recovery System
Fig. 4 Automatic Transmission Oil Cooler
NSCOOLING SYSTEM 7 - 3
GENERAL INFORMATION (Continued)

CONDITION - AND CHECKS DIAGNOSIS
Inadequate Air Conditioning Performance - Cooling System Suspected
(1) Check for plugged air side of condenser and
radiator front and rear.(1) Wash out with low-velocity water.
(2) Assure fan runs whenever A/C head pressure
exceeds 1724 kPa (250 psi).(2) Repair as necessary.
(3) Check for missing air seals-recirculating air path.
(4) Assure correct cooling system parts.
Battery Dead - Suspect Fan Current Draw as Cause
(1) With a good, fully charged battery. (1) a - Assure fan control is operating properly.
(1) b - See charging system in Electrical, Group 8B.
Hot Smell - Suspect Cooling System
(1) Was temperature gauge high? (1) a - Yes, See9Gauge Reads High9
(1) b - No. See 2, 3, 4, and 5.
(2) Heat shields all in place? (2) a - Yes, See 3, 4, and 5.
(2) b - Repair or replace heat shields.
(3) Fan control operating properly? (3) a - Yes, See 4 and 5.
(3) b - No, See Radiator Fan Control this section.
(4) Heat exchanger air side plugged? (4) Clean as required.
(5) Engine missing or running rich? (5) Repair as required.
Poor Driveability - Suspect Failed Open Thermostat.
(1) Check diagnostics - is code 17 set? (Engine too
cold for too long)(1) If yes, change thermostat.
Poor Heater Performance - Suspect Failed Open Thermostat
(1) Does gauge read low? (1) See 3
(2) Check coolant level. (2) See 3
(3) Check diagnostics - is code 17 set? (Engine too
cold for too long)(3) If yes, change thermostat. If no, check heater
bypass valve, which should be closed except in Max
A/C or off mode; if not, see Heater and Air Conditioning
Group, 24.
Steaming, Observe Water Vapor Through Grill or Head Gap at Standstill at Idle - In Wet Weather
(1) This is normal. It is moisture, snow, or water on the
outside of the radiator that evaporates when the
thermostat opens to put hot coolant into the radiator.
This usually occurs in cold weather with no fan or air
flow to blow it away.(1) Normal condition - no service required.
NSCOOLING SYSTEM 7 - 13
DIAGNOSIS AND TESTING (Continued)

WARNING: WITH TOOL IN PLACE, PRESSURE
WILL BUILD UP FAST. EXCESSIVE 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 emits from the tail pipe, it may
indicate a coolant leak caused by a faulty head gas-
ket, cracked engine block, or cracked cylinder head.
There may be internal leaks that can be deter-
mined by removing the oil dipstick. If water globules
appear intermixed with the oil it will indicate an
internal leak in the engine. If there is an internal
leak, the engine must be disassembled for repair.
RADIATOR CAP TO FILLER NECK SEAL PRESSURE
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. 13). Attach the
Radiator Pressure Tool to the filler neck nipple and
pump air into the radiator. Pressure cap upper gas-
ket should relieve at 69-124 kPa (10-18 psi) and hold
pressure at 55 kPa (8 psi) minimum.
WARNING: THE WARNING WORDS ªDO NOT
OPEN HOTº 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 OR UNDER PRESSURE.
There is no need to remove the radiator cap at any
timeexceptfor the following purposes:
(1) Check and adjust coolant freeze point. By add-
ing or subtracting coolant through CRS bottle.
(2) Refill system with new coolant.
(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 WITHOUT PUSHING DOWN ROTATE COUN-
TERCLOCKWISE TO THE FIRST STOP. ALLOW FLU-
IDS TO ESCAPE THROUGH THE OVERFLOW TUBE
AND WHEN THE SYSTEM STOPS PUSHING COOL-
ANT AND STEAM INTO THE CRS TANK AND PRES-
SURE DROPS PUSH DOWN AND REMOVE THE CAP
COMPLETELY. SQUEEZING THE RADIATOR INLET
HOSE WITH A SHOP TOWEL (TO CHECK PRES-
SURE) BEFORE AND AFTER TURNING TO THE
FIRST STOP IS RECOMMENDED.
PRESSURE TESTING RADIATOR CAP
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. SeeCAUTION.
If the pressure cap tests properly while positioned
on Radiator Pressure Tool (Fig. 14), 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 that will not cause cooling system
problems. A pressure cap that does not have a his-
tory 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.
LOW COOLANT LEVEL AERATION
Low coolant level in a cross flow radiator will
equalize in both tanks with engine off. With engine
Fig. 13 Radiator Pressure Cap Filler Neck
Fig. 14 Pressure Testing Radiator Cap
NSCOOLING SYSTEM 7 - 15
DIAGNOSIS AND TESTING (Continued)