oil temperature JEEP LIBERTY 2002 KJ / 1.G Service Manual

(11) Bleed fuel system. Refer to FUEL SYSTEM.
(12) Remove fuel rail.
(13) Remove throttle body assembly and mounting
bracket.
(14) Drain cooling system below coolant tempera-
ture level. Refer to COOLING SYSTEM.
(15) Remove the heater hoses from the engine
front cover and the heater core.
(16) Unclip and remove heater hoses and tubes
from intake manifold.
(17) Remove coolant temperature sensor. Refer to
FUEL SYSTEM.
(18) Remove intake manifold retaining fasteners in
reverse order of tightening sequence.
(19) Remove intake manifold.
INSTALLATION
(1) Install intake manifold gaskets.
(2) Install intake manifold.
(3) Install intake manifold retaining bolts and
tighten in sequence shown in to 12 N´m (105 in. lbs.).
(4) Install left and right radio suppressor straps.
(5) Install throttle body assembly.
(6) Install throttle cable bracket.
(7) Connect throttle cable and speed control cable
to throttle body.
(8) Install fuel rail.
(9) Install ignition coil towers.
(10) Position and install heater hoses and tubes
onto intake manifold.
(11) Install the heater hoses to the heater core and
engine front cover.
(12) Connect electrical connectors for the following
components:
²Manifold Absolute Pressure (MAP) Sensor
²Intake Air Temperature (IAT) Sensor
²Throttle Position (TPS) Sensor
²Coolant Temperature (CTS) Sensor
²Idle Air Control (IAC) Motor
²Ignition coil towers
²Fuel injectors
(13) Install top oil dipstick tube retaining bolt and
ground strap.
(14) Connect generator electrical connections.
(15) Connect Vapor purge hose, Brake booster
hose, Speed control servo hose, Positive crankcase
ventilation (PCV) hose.
(16) Fill cooling system.
(17) Install resonator assembly and air inlet hose.
(18) Connect negative cable to battery.
EXHAUST MANIFOLD
DESCRIPTION
The exhaust manifolds (Fig. 87) are log style with
a patented flow enhancing design to maximize perfor-
mance. The exhaust manifolds are made of high sili-
con molybdenum cast iron. A perforated core graphite
exhaust manifold gasket is used to improve sealing
to the cylinder head. The exhaust manifolds are cov-
ered by a three layer laminated heat shield for ther-
mal protection and noise reduction. The heat shields
(Fig. 88) are fastened with a torque prevailing nut
that is backed off slightly to allow for the thermal
expansion of the exhaust manifold.
REMOVAL
RIGHT EXHAUST MANIFOLD
(1) Disconnect the negative cable from the battery.
(2) Raise and support the vehicle.
(3) Remove the bolts and nuts attaching the
exhaust pipe to the engine exhaust manifold.
(4) Lower the vehicle.
(5) Remove the exhaust heat shield (Fig. 89).
(6) Remove bolts, nuts and washers attaching
manifold to cylinder head.
(7) Remove manifold and gasket from the cylinder
head.
Fig. 87 EXHAUST MANIFOLDS
1 - LEFT SIDE EXHAUST MANIFOLD
2 - RIGHT SIDE EXHAUST MANIFOLD
KJENGINE - 3.7L 9 - 69
INTAKE MANIFOLD (Continued)

ENGINE - 2.4L
DESCRIPTION
The 2.4 Liter (148 cu. in.) in-line four cylinder
engine is a double over head camshaft with hydraulic
lifters and four valve per cylinder design. The engine
is free-wheeling; meaning it has provisions for piston-
to-valve clearance. However valve-to-valve interference
can occur, if camshafts are rotated independently.
The cylinders are numbered from front of the
engine to the rear. The firing order is 1±3±4±2.
The engine identification number is located on the
rear of the cylinder block (Fig. 1).
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - CYLINDER
COMBUSTION PRESSURE LEAKAGE TEST
The combustion pressure leakage test provides an
accurate means for determining engine condition.
Combustion pressure leakage testing will detect:
²Exhaust and intake valve leaks (improper seat-
ing).
²Leaks between adjacent cylinders or into water
jacket.
²Any causes for combustion/compression pressure
loss.WARNING: DO NOT REMOVE THE PRESSURE CAP
WITH THE SYSTEM HOT AND UNDER PRESSURE
BECAUSE SERIOUS BURNS FROM COOLANT CAN
OCCUR.
Check the coolant level and fill as required. DO
NOT install the pressure cap.
Start and operate the engine until it attains nor-
mal operating temperature, then turn the engine
OFF.
Clean spark plug recesses with compressed air.
Remove the spark plugs.
Remove the oil filler cap.
Remove the air cleaner.
Calibrate the tester according to the manufactur-
er's instructions. The shop air source for testing
should maintain 483 kPa (70 psi) minimum, 1,379
kPa (200 psi) maximum, with 552 kPa (80 psi) rec-
ommended.
Perform the test procedures on each cylinder
according to the tester manufacturer's instructions.
While testing, listen for pressurized air escaping
through the throttle body, tailpipe and oil filler cap
opening. Check for bubbles in the coolant.
All gauge pressure indications should be equal,
with no more than 25% leakage per cylinder.
FOR EXAMPLE:At 552 kPa (80 psi) input pres-
sure, a minimum of 414 kPa (60 psi) should be main-
tained in the cylinder.
DIAGNOSIS AND TESTING - CYLINDER
COMPRESSION PRESSURE TEST
The results of a cylinder compression pressure test
can be utilized to diagnose several engine malfunc-
tions.
Ensure the battery is completely charged and the
engine starter motor is in good operating condition.
Otherwise the indicated compression pressures may
not be valid for diagnosis purposes.
(1) Check engine oil level and add oil if necessary.
(2) Drive the vehicle until engine reaches normal
operating temperature. Select a route free from traf-
fic and other forms of congestion, observe all traffic
laws, and accelerate through the gears several times
briskly.
(3) Remove all spark plugs from engine. As spark
plugs are being removed, check electrodes for abnor-
mal firing indicators fouled, hot, oily, etc. Record cyl-
inder number of spark plug for future reference.
(4) Remove the Auto Shutdown (ASD) relay from
the PDC.
(5) Be sure throttle blade is fully open during the
compression check.
(6) Insert compression gage adaptor Special Tool
8116 or the equivalent, into the #1 spark plug hole in
cylinder head. Connect the 0±500 psi (Blue) pressure
transducer with cable adaptors to the DRBIIIt.
Fig. 1 ENGINE IDENTIFICATION
1 - ENGINE IDENTIFICATION
KJENGINE9s-3

DIAGNOSIS AND TESTING - ENGINE MECHANICAL
CONDITION POSSIBLE CAUSES CORRECTION
NOISY VALVES 1. High or low oil level in
crankcase.1. Check and correct engine oil
level.
2. Thin or diluted oil. 2. Change oil to correct viscosity.
3. Thick oil 3. (a) Change engine oil and filter.
(b) Run engine to operating
temperature.
(c) Change engine oil and filter
again.
4. Low oil pressure. 4. Check and correct engine oil
level.
5. Dirt in tappets/lash adjusters. 5. Replace rocker arm/hydraulic
lash adjuster assembly.
6. Worn rocker arms. 6. Inspect oil supply to rocker arms.
7. Worn tappets/lash adjusters. 7. Install new rocker arm/hydraulic
lash adjuster assembly.
8. Worn valve guides. 8. Replace cylinder head assembly.
9. Excessive runout of valve seats
on valve faces.9. Grind valve seats and valves.
10. Missing adjuster pivot. 10. Replace rocker arm/hydraulic
lash adjuster assembly.
CONNECTING ROD NOISE 1. Insufficient oil supply. 1. Check engine oil level.
2. Low oil pressure. 2. Check engine oil level. Inspect oil
pump relief valve and spring.
3. Thin or diluted oil. 3. Change oil to correct viscosity.
4. Thick oil 4. (a) Change engine oil and filter.
(b) Run engine to operating
temperature.
(c) Change engine oil and filter
again.
5. Excessive bearing clearance. 5. Measure bearings for correct
clearance. Repair as necessary.
6. Connecting rod journal
out-of-round.6. Replace crankshaft or grind
surface.
7. Misaligned connecting rods. 7. Replace bent connecting rods.
KJENGINE9s-7
ENGINE - 2.4L (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
MAIN BEARING NOISE 1. Insufficient oil supply. 1. Check engine oil level.
2. Low oil pressure. 2. Check engine oil level. Inspect oil
pump relief valve and spring.
3. Thin or diluted oil. 3. Change oil to correct viscosity.
4. Thick oil 4. (a) Change engine oil and filter.
(b) Run engine to operating
temperature.
(c) Change engine oil and filter
again.
5. Excessive bearing clearance. 5. Measure bearings for correct
clearance. Repair as necessary.
6. Excessive end play. 6. Check thrust bearing for wear on
flanges.
7. Crankshaft journal out-of-round
or worn.7. Replace crankshaft or grind
journals.
8. Loose flywheel or torque
converter.8. Tighten to correct torque.
OIL PRESSURE DROP 1. Low oil level. 1. Check engine oil level.
2. Faulty oil pressure sending unit. 2. Install new sending unit.
3. Low oil pressure. 3. Check sending unit and main
bearing oil clearance.
4. Clogged oil filter. 4. Install new oil filter.
5. Worn parts in oil pump. 5. Replace worn parts or pump.
6. Thin or diluted oil. 6. Change oil to correct viscosity.
7. Oil pump relief valve stuck. 7. Replace oil pump.
8. Oil pump suction tube loose. 8. Remove oil pan and install new
tube or clean, if necessary.
9. Oil pump cover warped or
cracked.9. Install new oil pump.
10. Excessive bearing clearance. 10. Measure bearings for correct
clearance.
OIL LEAKS 1. Misaligned or deteriorated
gaskets.1. Replace gasket(s).
2. Loose fastener, broken or porous
metal part.2. Tighten, repair or replace the
part.
3. Misaligned or deteriorated cup or
threaded plug.3. Replace as necessary.
9s - 8 ENGINEKJ
ENGINE - 2.4L (Continued)

NOTE: Plastigage is available in a variety of clear-
ance ranges. Use the most appropriate range for
the specifications you are checking.
(4) Install the proper crankshaft bearings to
achieve the specified bearing clearances. (Refer to 9 -
ENGINE/ENGINE BLOCK/CRANKSHAFT MAIN
BEARINGS - STANDARD PROCEDURE) (Refer to 9
- ENGINE/ENGINE BLOCK/CONNECTING ROD
BEARINGS - STANDARD PROCEDURE)
REMOVAL - ENGINE ASSEMBLY
(1) Disconnect the battery negative cable.
(2) Remove hood. Mark hood hinge location for
reinstallation.
(3) Remove air cleaner assembly.
(4) Remove radiator core support bracket.
(5) Remove fan shroud with electric fan assembly.
(6) Remove drive belt.
NOTE: It is NOT necessary to discharge the A/C
system to remove the engine.
(7) Remove A/C compressor and secure away from
engine with lines attached.
(8) Remove generator and secure away from
engine.
NOTE: Do NOT remove the phenolic pulley from the
P/S pump. It is not required for P/S pump removal.
(9) Remove power steering pump with lines
attached and secure away from engine.
(10) Drain cooling system.
(11) Remove coolant bottle.
(12) Disconnect the heater hoses from the engine.
(13) Disconnect heater hoses from heater core and
remove hose assembly.
(14) Disconnect throttle and speed control cables.
(15) Remove upper radiator hose from engine.
(16) Remove lower radiator hose from engine.
(17) Disconnect the engine to body ground straps
at the left side of cowl.
(18) Disconnect the engine wiring harness at the
following points:
²Intake air temperature (IAT) sensor
²Fuel Injectors
²Throttle Position (TPS) Switch
²Idle Air Control (IAC) Motor
²Engine Oil Pressure Switch
²Engine Coolant Temperature (ECT) Sensor
²Manifold Absolute Pressure MAP) Sensor
²Camshaft Position (CMP) Sensor
²Coil Over Plugs
²Crankshaft Position Sensor
(19) Remove coil over plugs.
(20) Release fuel rail pressure.(21) Remove fuel rail and secure away from
engine.
(22) Remove the PCV hose.
(23) Remove the breather hoses.
(24) Remove the vacuum hose for the power brake
booster.
(25) Disconnect knock sensors.
(26) Secure the left and right engine wiring har-
nesses away from engine.
(27) Raise vehicle.
(28) Disconnect oxygen sensor wiring.
(29) Disconnect crankshaft postion sensor.
(30) Disconnect the engine block heater power
cable, if equipped.
(31) Disconnect the front propshaft at the front
differential and secure out of way.
(32) Remove the starter.
(33) Remove the ground straps from the engine
(34) Disconnect the exhaust pipes at the manifold.
(35) Remove the structural cover, if equipped.
(36) Remove torque convertor bolts, and mark
location for reassembly.
(37) Remove transmission bellhousing to engine
bolts.
(38) Loosen left and right engine mount thru bolts.
NOTE: It is not necessary to completely remove
engine mount thru bolts, for engine removal.
(39) Lower the vehicle.
(40) Support the transmission with a suitable jack.
(41) Connect a suitable engine hoist to the engine.
CAUTION: The 2.4L engine with manual transmis-
sions, can be removed without removing the man-
ual transmission. Use caution when attempting this
procedure as the clearance is tight.
(42) Remove engine from vehicle.
INSTALLATION - ENGINE ASSEMBLY
(1) Position the engine in the vehicle.
CAUTION: Use caution when installing 2.4L engine
into vehicle equipped with manual transmission, as
clearance is tight.
(2) Install both left and right side engine mounts
into the frame mounts.
(3) Raise the vehicle.
(4) Install the transmission bellhousing to engine
mounting bolts. Tighten the bolts to 41 N´m (30ft.
lbs.).
(5) Tighten the engine mount thru bolts.
(6) Install the torque convertor bolts.
(7) Connect the ground straps on the left and right
side of the engine.
9s - 12 ENGINEKJ
ENGINE - 2.4L (Continued)

(8) Install the starter.
(9) Connect the crankshaft position sensor.
(10) Install the engine block heater power cable, if
equipped.
CAUTION: The structural cover requires a specific
torque sequence. Failure to follow this sequence
may cause severe damage to the cover.
(11) Install the structural cover.
(12) Install the exhaust pipe.
(13) Connect the oxygen sensors.
(14) Lower vehicle.
(15) Connect the knock sensors.
(16) Connect the engine to body ground straps.
(17) Install the power brake booster vacuum hose.
(18) Install the breather hoses.
(19) Install the PCV hose.
(20) Install the fuel rail.
(21) Install the coil over plugs.
(22) Reconnect the engine wiring harness at the
following points:
²Intake air temperature (IAT) sensor
²Fuel Injectors
²Throttle Position (TPS) Switch
²Idle Air Control (IAC) Motor
²Engine Oil Pressure Switch
²Engine Coolant Temperature (ECT) Sensor
²Manifold Absolute Pressure MAP) Sensor
²Camshaft Position (CMP) Sensor
²Coil Over Plugs
²Crankshaft Position Sensor
(23) Connect lower radiator hose.
(24) Connect upper radiator hose.
(25) Connect throttle and speed control cables.
(26) Install the heater hose assembly.
(27) Install coolant recovery bottle.
(28) Install the power steering pump.
(29) Install the generator.
(30) Install the A/C compressor.
(31) Install the drive belt.
(32) Install the fan shroud with the electric fan
assembly.
(33) Install the radiator core support bracket.
(34) Install the air cleaner assembly.
(35) Refill the engine cooling system.
(36) Install the hood.
(37) Check and fill engine oil.
(38) Connect the battery negative cable.
(39) Start the engine and check for leaks.SPECIFICATIONS
SPECIFICATIONS - 2.4L ENGINE
DESCRIPTION SPECIFICATION
General Specification
Type In-Line OHV, DOHC
Number of Cylinders 4
Displacement 2.4 Liters
(148 cu. in.)
Bore 87.5 mm
(3.445 in.)
Stroke 101.0 mm
(3.976 in.)
Compression Ratio 9.4:1
Firing Order 1-3-4-2
Compression Pressure 690 kPa (Minimum)
(100 psi Minimum)
Max. Variation Between
Cylinders25%
Cylinder Block
Cylinder Bore Diameter 87.4924±87.5076 mm
(3.4446±3.4452 in.)
Out-of-Round (Max.) 0.051 mm
(0.002 in.)
Taper (Max.) 0.051 mm
(0.002 in.)
Pistons
Piston Diameter 87.463±87.481 mm
(3.4434±3.4441 in.)
Clearance @ 14 mm
(9/16 in.) from bottom of
skirt0.024±0.057 mm
(0.0009±0.0022 in.)
Weight 346±356 grams
(12.20±12.56 oz.)
Land Clearance
(Diametrical)0.614±0.664 mm
(0.024±0.026 in.)
Piston Length 66.25 mm
(2.608 in.)
Piston Ring Groove
Depth No. 14.640±4.784 mm
(0.182±0.188 in.)
Piston Ring Groove
Depth No. 24.575±4.719 mm
(0.180±0.185 in.)
KJENGINE9s-13
ENGINE - 2.4L (Continued)

(2) Insufficient running time after rebuilding cylin-
der head. Low speed running up to 1 hour may be
required.
(3) During this time, turn engine off and let set for
a few minutes before restarting. Repeat this several
times after engine has reached normal operating
temperature.
(4) Low oil pressure.
(5) The oil restrictor (integral to the head gasket)
in the vertical oil passage to the cylinder head is
plugged with debris.
(6) Air ingested into oil due to broken or cracked
oil pump pick up.
(7) Worn valve guides.
(8) Rocker arm ears contacting valve spring
retainer.
(9) Rocker arm loose, adjuster stuck or at maxi-
mum extension and still leaves lash in the system.
(10) Faulty lash adjuster.
a. Check lash adjusters for sponginess while
installed in cylinder head. Depress part of rocker
arm over adjuster. Normal adjusters should feel very
firm. Spongy adjusters can be bottomed out easily.
b. Remove suspected lash adjusters, and replace as
necessary.
REMOVAL
NOTE: This procedure is for in-vehicle service with
camshafts installed.
(1) Remove cylinder head cover. (Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - REMOVAL)
(2) Remove the camshafts (Refer to 9 - ENGINE/
CYLINDER HEAD/CAMSHAFT(S) - REMOVAL).
(3) Remove rocker arm. (Refer to 9 - ENGINE/
CYLINDER HEAD/ROCKER ARMS - REMOVAL)
(4) Remove hydraulic lifter (Fig. 30).(5) Repeat removal procedure for each hydraulic
lifter.
(6) If reusing, mark each hydraulic lifter for reas-
sembly in original position. Lifters are serviced as an
assembly.
INSTALLATION
(1) Install hydraulic lifter (Fig. 30). Ensure the
lifters are at least partially full of engine oil. This is
indicated by little or no plunger travel when the
lifter is depressed.
(2) Install rocker arm. (Refer to 9 - ENGINE/CYL-
INDER HEAD/ROCKER ARMS - INSTALLATION)
(3) Repeat installation procedure for each hydrau-
lic lifter.
(4) Install camshafts (Refer to 9 - ENGINE/CYL-
INDER HEAD/CAMSHAFT(S) - INSTALLATION).
(5) Install cylinder head cover. (Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - INSTALLATION)
ROCKER ARMS
REMOVAL
NOTE: This procedure is for in-vehicle service with
camshafts installed.
(1) Remove cylinder head cover. (Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - REMOVAL)
(2) Remove fuel rail. (Refer to 14 - FUEL SYS-
TEM/FUEL DELIVERY/FUEL RAIL - REMOVAL)
(3) Remove spark plugs.
(4) Rotate engine until the camshaft lobe, on the
follower being removed, is position on its base circle
(heel). Also, the piston should be a minimum of 6.3
mm (0.25 in) below TDC position.
Fig. 29 Checking Spring Installed Height and Valve
Tip Height Dimensions
1 - GARTER SPRING
2 - VALVE SPRING SEAT
3 - CYLINDER HEAD SURFACE
Fig. 30 Hydraulic Lash Adjuster
KJENGINE9s-29
HYDRAULIC LIFTERS (Continued)

shown in (Fig. 34). Refer to for Engine Specifications
(Refer to 9 - ENGINE - SPECIFICATIONS). Correct
piston to bore clearance must be established in order
to assure quiet and economical operation.
NOTE: Pistons and cylinder bores should be mea-
sured at normal room temperature, 21ÉC (70ÉF).
STANDARD PROCEDURE - CYLINDER BORE
HONING
(1) Used carefully, the cylinder bore resizing hone,
recommended tool C-823 or equivalent, equipped
with 220 grit stones, is the best tool for this honing
procedure. In addition to deglazing, it will reduce
taper and out-of-round as well as removing light
scuffing, scoring or scratches. Usually a few strokes
will clean up a bore and maintain the required lim-
its.
(2) Deglazing of the cylinder walls may be done
using a cylinder surfacing hone, recommended toolC-3501 or equivalent, equipped with 280 grit stones,
if the cylinder bore is straight and round. 20±60
strokes depending on the bore condition, will be suf-
ficient to provide a satisfactory surface. Use a light
honing oil.Do not use engine or transmission oil,
mineral spirits or kerosene.Inspect cylinder walls
after each 20 strokes.
(3) Honing should be done by moving the hone up
and down fast enough to get a cross-hatch pattern.
When hone marksintersectat 40-60 degrees, the
cross hatch angle is most satisfactory for proper seat-
ing of rings (Fig. 36).
(4) A controlled hone motor speed between
200±300 RPM is necessary to obtain the proper cross-
hatch angle. The number of up and down strokes per
minute can be regulated to get the desired 40±60
degree angle. Faster up and down strokes increase
the cross-hatch angle.
(5) After honing, it is necessary that the block be
cleaned again to remove all traces of abrasive.
CAUTION: Ensure all abrasives are removed from
engine parts after honing. It is recommended that a
solution of soap and hot water be used with a
brush and the parts then thoroughly dried. The bore
can be considered clean when it can be wiped
clean with a white cloth and cloth remains clean.
Oil the bores after cleaning to prevent rusting.
CLEANING
Clean cylinder block thoroughly using a suitable
cleaning solvent.
Fig. 34 Checking Cylinder Bore -Typical
Fig. 35 Piston Measurement - Typical
Fig. 36 Cylinder Bore Cross-Hatch Pattern
1 - CROSS-HATCH PATTERN
2 - 40ɱ60É
KJENGINE9s-31
ENGINE BLOCK (Continued)

INSPECTION
ENGINE BLOCK
(1) Clean cylinder block thoroughly and check all
core hole plugs for evidence of leaking.
(2) If new core plugs are to be installed, (Refer to 9
- ENGINE - STANDARD PROCEDURE - ENGINE
CORE AND OIL GALLERY PLUGS).
(3) Examine block and cylinder bores for cracks or
fractures.
(4) Check block deck surfaces for flatness. Deck
surface must be within service limit of 0.1 mm (0.004
in.).
CYLINDER BORE
NOTE: The cylinder bores should be measured at
normal room temperature, 21ÉC (70ÉF).
The cylinder walls should be checked for out-of-
round and taper with Tool C119 or equivalent (Fig.
37) (Refer to 9 - ENGINE - SPECIFICATIONS). If
the cylinder walls are badly scuffed or scored, the
cylinder block should be replaced, and new pistons
and rings fitted.
Measure the cylinder bore at three levels in direc-
tions A and B (Fig. 37). Top measurement should be
10 mm (3/8 in.) down and bottom measurement
should be 10 mm (3/8 in.) up from bottom of bore.
(Refer to 9 - ENGINE - SPECIFICATIONS).
CONNECTING ROD BEARINGS
STANDARD PROCEDURE
CONNECTING ROD - FITTING
(1) For measuring connecting rod bearing clear-
ance procedure and use of Plastigage(Refer to 9 -
ENGINE - STANDARD PROCEDURE). For bearing
clearance refer to Engine Specifications. (Refer to 9 -
ENGINE - SPECIFICATIONS)
NOTE: The rod bearing bolts should not be reused.
(2) Before installing theNEWbolts the threads
should be oiled with clean engine oil.
(3) Install each bolt finger tight then alternately
torque each bolt to assemble the cap properly.
(4) Tighten the bolts to 27 N´m PLUS 1/4 turn (20
ft. lbs. PLUS 1/4 turn)Do not use a torque
wrench for last step.
(5) Using a feeler gauge, check connecting rod side
clearance (Fig. 38). Refer to clearance specifications
(Refer to 9 - ENGINE - SPECIFICATIONS).
CRANKSHAFT
DESCRIPTION
The crankshaft is made of nodular cast iron and
includes five main bearing journals and four connect-
ing rod journals (Fig. 39). The number three journal
is the location for the thrust bearing. The mains and
connecting rod journals have undercut fillet radiuses
that are rolled for added strength. To optimize bear-
ing loading, eight counterweights are used.
Fig. 37 Checking Cylinder Bore Size
Fig. 38 Connecting Rod Side Clearance
9s - 32 ENGINEKJ
ENGINE BLOCK (Continued)

DESCRIPTION - REFRIGERANT SYSTEM
SERVICE PORT
The two refrigerant system service ports are used
to charge, recover/recycle, evacuate, and test the air
conditioning refrigerant system. Unique service port
coupler sizes are used on the R-134a system, to
ensure that the refrigerant system is not accidentally
contaminated by the use of the wrong refrigerant
(R-12), or refrigerant system service equipment.
OPERATION
OPERATION - HEATER AND AIR CONDITIONER
The heater and optional air conditioner are blend-
air type systems. In a blend-air system, a blend door
controls the amount of unconditioned air (or cooled
air from the evaporator on models with air condition-
ing) that is allowed to flow through, or around, the
heater core. A temperature control knob on the A/C
Heater control panel determines the discharge air
temperature by controlling an electric actuator,
which moves the blend door. This allows an almost
immediate control of the output air temperature of
the system.
The mode control knob on the heater-only or A/C
Heater control panel is used to direct the conditioned
air to the selected system outlets. Both mode control
switches use engine vacuum to control the mode
doors, which are operated by vacuum actuators.
On all vehicles, the outside air intake can be shut
off by selecting the Recirculation Mode with the
mode control knob. This will operate a vacuum actu-
ated recirculation door that closes off the outside
fresh air intake and recirculates the air that is
already inside the vehicle.
The optional air conditioner for all models is
designed for the use of non-CFC, R-134a refrigerant.
The air conditioning system has an evaporator to cool
and dehumidify the incoming air prior to blending it
with the heated air. This air conditioning system
uses a fixed orifice tube in the liquid line near the
condenser outlet tube to meter refrigerant flow to the
evaporator coil. To maintain minimum evaporator
temperature and prevent evaporator freezing, the
A/C low pressure switch on the accumulator cycles
the compressor clutch.
OPERATION - REFRIGERANT SYSTEM SERVICE
PORT
The high pressure service port is located on the
refrigerant line, near the discharge port of the com-
pressor. The low pressure service port is located on
the liquid line at the side of the engine compartment,
near the condensor.Each of the service ports has a threaded plastic
protective cap installed over it from the factory. After
servicing the refrigerant system, always reinstall
both of the service port caps.
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - A/C
PERFORMANCE
The air conditioning system is designed to provide
the passenger compartment with low temperature
and low humidity air. The evaporator, located in the
HVAC housing on the dash panel below the instru-
ment panel, is cooled to temperatures near the freez-
ing point. As warm damp air passes through the
cooled evaporator, the air transfers its heat to the
refrigerant in the evaporator and the moisture in the
air condenses on the evaporator fins. During periods
of high heat and humidity, an air conditioning sys-
tem will be more effective in the Recirculation Mode.
With the system in the Recirculation Mode, only air
from the passenger compartment passes through the
evaporator. As the passenger compartment air dehu-
midifies, the air conditioning system performance
levels improve.
Humidity has an important bearing on the temper-
ature of the air delivered to the interior of the vehi-
cle. It is important to understand the effect that
humidity has on the performance of the air condition-
ing system. When humidity is high, the evaporator
has to perform a double duty. It must lower the air
temperature, and it must lower the temperature of
the moisture in the air that condenses on the evapo-
rator fins. Condensing the moisture in the air trans-
fers heat energy into the evaporator fins and tubing.
This reduces the amount of heat the evaporator can
absorb from the air. High humidity greatly reduces
the ability of the evaporator to lower the temperature
of the air.
However, evaporator capacity used to reduce the
amount of moisture in the air is not wasted. Remov-
ing some of the moisture out of the air entering the
vehicle adds to the comfort of the passengers.
Although, an owner may expect too much from the
air conditioning system on humid days. A perfor-
mance test is the best way to determine whether the
system is performing up to standard. This test also
provides valuable clues as to the possible cause of
trouble with the air conditioning system.
Before proceeding, (Refer to 24 - HEATING & AIR
CONDITIONING/PLUMBING - WARNING) and
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - CAUTION). The air temperature in
the test room and in the vehicle must be a minimum
of 21É C (70É F) for this test.
24 - 2 HEATING & AIR CONDITIONINGKJ
HEATING & AIR CONDITIONING (Continued)