²Check glow plug operation.
²Replace drive belt.
²Check engine smoke.
²Replace engine coolant.
35 000 KM
²Change engine oil.
²Change engine oil filter.
²Change MTX Fluid
40 000 KM
²Change engine oil.
²Change engine oil filter.
²Replace air filter element.
²Check drive belt tension.
²Check glow plug operation.
²Diesel engines onlyÐReplace fuel filter/water
separator element.
45 000 KM
²Change engine oil.
²Change engine oil filter.
50 000 KM
²Change engine oil.
²Change engine oil filter.
²Replace air filter element.
²Check drive belt tension.
²Check glow plug operation.
55 000 KM
²Change engine oil.
²Change engine oil filter.
60 000 KM
²Change engine oil.
²Change engine oil filter.
²Replace air filter element.
²Check drive belt tension.
²Check glow plug operation.
²Diesel engines onlyÐReplace fuel filter/water
separator element.
65 000 KM
²Change engine oil.
²Change engine oil filter.
70 000 KM
²Change engine oil.
²Change engine oil filter.
²Replace air filter element.
²Check drive belt tension.
²Check glow plug operation.
²Change MTX fluid
75 000 KM
²Change engine oil.
²Change engine oil filter.
80 000 KM
²Change engine oil.
²Change engine oil filter.
²Replace air filter element.
²Check glow plug operation.
²Replace drive belt.
²Check engine smoke.
²Replace engine coolant.
85 000 KM
²Change engine oil.
²Change engine oil filter.
90 000 KM
²Change engine oil.
²Change engine oil filter.
²Replace air filter element.
²Check drive belt tension.
²Check glow plug operation.
95 000 KM
²Change engine oil.
²Change engine oil filter.
100 000 KM
²Change engine oil.
²Change engine oil filter.
²Replace air filter element.
²Check drive belt tension.
²Check glow plug operation.
²Diesel engines onlyÐReplace fuel filter/water
separator element.
²Change MTX fluid
EVERY 5 000 KM AFTER 100 000 KM
²Change engine oil.
²Change engine oil filter.
EVERY 10 000 KM AFTER 100 000 KM
²Change engine oil.
²Change engine oil filter.
²Replace air filter element.
²Check drive belt tension.
²Check glow plug operation.
EVERY 20 000 KM AFTER 100 000 KM
²Diesel engines onlyÐReplace fuel filter/water
separator element.
EVERY 35 000 KM AFTER 100 000 KM
²Change MTX fluid
0 - 4 LUBRICATION AND MAINTENANCENS/GS
GENERAL INFORMATION (Continued)
INSTALLATION
(1) Place a new gasket (dipped in water) on the
thermostat housing surface, center thermostat into
opening in the intake manifold water box.
(2) Place housing and gasket over the thermostat,
making sure thermostat is in the recess provided
(Fig. 28).
(3) Bolt housing to intake manifold, tighten bolts
to 28 N´m (250 in. lbs.).
(4) Refill the cooling system to the proper level.
Refer to Cooling System Refilling outlined in this sec-
tion for procedure.
RADIATOR
REMOVAL
(1) Disconnect negative cable from battery.
WARNING: DO NOT REMOVE THE CYLINDER
BLOCK PLUG OR THE RADIATOR DRAINCOCK
WITH THE SYSTEM HOT AND UNDER PRESSURE
BECAUSE SERIOUS BURNS FROM COOLANT CAN
OCCUR.
(2) Drain cooling system. Refer to Draining Cool-
ing System of this section.
(3) Remove air intake resonator.
(4) Remove coolant reserve system tank to filler
neck tube hose.
(5) Disconnect fans from the connector located on
the left side of the fan module.
(6) Remove the Coolant Recovery System (CRS)
tank retaining screw from the upper radiator closure
panel crossmember.
(7) Disconnect the upper radiator mounting
screws from the crossmember. Disconnect the engine
block heater wire if equipped.
(8) Remove the upper radiator closure panel
crossmember. Refer to Group 23 Body for procedure.
(9) Remove air cleaner assembly.
(10) Disconnect automatic transmission oil cooler
lines at radiator and plug.
(11) Disconnect inlet and outlet hoses from the
radiator. Remove the lower hose clip from the fan
module.
(12) Remove A/C condenser fasteners and sepa-
rate the condenser from the radiator (Fig. 29). Verify
the condenser is supported in position.
(13) Remove A/C filter/dryer mounting bracket, 2
bolts to the fan module, and 2 nuts to the filter/dryer.
(14) Radiator can now be lifted free from engine
compartment.Care should be taken not to dam-
age radiator cooling fins or water tubes during
removal.INSTALLATION
(1)Be sure the air seals are in position before
radiator is installed.Slide radiator down into posi-
tion behind closure panel. Seat the radiator with the
rubber isolators into the mounting holes provided,
with a 10 lbs. force.
(2) Install A/C filter/dryer and mounting bracket
onto fan module.
(3) Install Air Conditioning Condenser onto the
radiator (Fig. 29).
(4) Unplug and connect automatic transmission
oil cooler lines to radiator.
(5) Install inlet and outlet radiator hoses (includ-
ing coolant reserve hose) and connect the fan motor
electrical connection.
(6) Install air cleaner assembly.
(7) Install the upper radiator closure panel cross-
member. Refer to Group 23 Body for procedure.
(8) Install the upper radiator mounting screws.
Tighten radiator mounting bolts to 12 N´m (105 in.
lbs.). Connect the engine block heater wire if
equipped.
(9) Install the Coolant Recovery System (CRS)
tank retaining screw to the upper radiator closure
panel crossmember.
(10) Install air intake resonator.
(11) Fill cooling system. Refer to Cooling System
Filling in this section.
(12) Connect negative cable to battery.
RADIATOR DRAINCOCK
REMOVAL
CAUTION: Use of pliers on draincock is not rec-
ommended. Damage may occur to part. Draincock
should not be removed unless leakage observed.
(1) Turn the draincock stem counterclockwise to
unscrew the stem. When the stem is unscrewed to
Fig. 29 Air Conditioning Condenser Mounting
Fasteners
NSCOOLING SYSTEM 7 - 21
REMOVAL AND INSTALLATION (Continued)
Initial belt adjustment is done with a adjustable
tensioner pulley. After the initial adjustment is per-
formed, an automatic belt tensioner is used to main-
tain correct belt tension at all times. Do not attempt
to check belt tension with a belt tension gauge on
vehicles equipped with an automatic belt tensioner.
Refer to Automatic Belt Tensioner in this group.
AUTOMATIC BELT TENSIONER
Drive belt tension is controlled by a spring loaded
automatic belt tensioner located below and to the
front of the engine oil filter (Fig. 12). This tensioner
is connected to a pivot bracket and a pulley (Fig. 12).
The pivot bracket rotates on a pivot pin attached to
the engine. Special machined washers with rubber
o-rings (Fig. 12) are used at each side of the pivot
bracket to help keep dirt and water away from the
pivot pin.
If a defective belt tensioner is suspected, a check of
this pivot bracket and pivot pin should be made. Cor-
rosion may have formed at the pin and may cause
the pivot bracket to stick. Belt slippage will result.
WARNING: BECAUSE OF HIGH SPRING PRES-
SURE, DO NOT ATTEMPT TO DISASSEMBLE THE
AUTOMATIC BELT TENSIONER. UNIT IS SERVICED
AS AN ASSEMBLY.
THERMOSTAT
DIAGNOSIS
Diesel engines, due to their inherent efficiency are
slower to warm up than gasoline powered engines,
and will operate at lower temperatures when the
vehicle is unloaded. Because of this, lower tempera-
ture gauge readings for diesel versus gasoline
engines may, at times be normal.
Typically, complaints of low engine coolant temper-
ature are observed as low heater output when com-
bined with cool or cold outside temperatures.
To help promote faster engine warm-up, an electric
engine block heater must be used with cool or cold
outside temperatures. This will help keep the engine
coolant warm when the vehicle is parked. Use the
block heater if the outside temperature is below 4ÉC
(40ÉF).Do not use the block heater if the out-
side temperature is above 4ÉC (40ÉF).
TESTING
NOTE: The DRB scan tool shoud be used to moni-
tor engine coolant temperature on the diesel
engine. Refer to the 1998 GS Powertrain Diagnostic
Manual for thermostat diagnosis procedure.
Fig. 12 Automatic Belt Tensioner Assembly
7 - 6 COOLING SYSTEMNS/GS
DESCRIPTION AND OPERATION (Continued)
engine is operating, the smaller the pulse width on
the oscilloscope.
By counting the pulses and referencing the pulse
from the 60 degree signature notch, the PCM calcu-
lates crankshaft angle (position). In each group of
timing reference notches, the first notch represents
69 degrees before top dead center (BTDC). The sec-
ond notch represents 49 degrees BTDC. The third
notch represents 29 degrees. The last notch in each
set represents 9 degrees before top dead center
(TDC).
The timing reference notches are machined to a
uniform width representing 13.6 degrees of crank-
shaft rotation. From the voltage pulse width the
PCM tells the difference between the timing refer-
ence notches and the 60 degree signature notch. The
60 degree signature notch produces a longer pulse
width than the smaller timing reference notches. If
the camshaft position sensor input switches from
high to low when the 60 degree signature notch
passes under the crankshaft position sensor, the
PCM knows cylinder number one is the next cylinder
at TDC.
The crankshaft position sensor mounts to the
engine block behind the generator, near the oil filter
(Fig. 8).
CAMSHAFT POSITION SENSOR
The PCM determines fuel injection synchronization
and cylinder identification from inputs provided by
the camshaft position sensor and crankshaft position
sensor. From the two inputs, the PCM determines
crankshaft position.The camshaft position sensor attaches to the rear
of the cylinder head (Fig. 2). A target magnet
attaches to the rear of the camshaft and indexes to
the correct position (Fig. 3). The target magnet has
four different poles arranged in an asymmetrical pat-
tern. As the target magnet rotates, the camshaft
position sensor senses the change in polarity (Fig. 4).
The sensor output switch switches from high (5.0
volts) to low (0.30 volts) as the target magnet rotates.
When the north pole of the target magnet passes
under the sensor, the output switches high. The sen-
sor output switches low when the south pole of the
target magnet passes underneath.
INTAKE AIR TEMPERATURE SENSORÐ2.4L
The intake air temperature sensor measures the
temperature of the air as it enters the engine. The
sensor supplies one of the inputs the PCM uses to
determine injector pulse width and spark advance.
The intake air temperature sensor threads into the
intake manifold (Fig. 5).
Fig. 2 Crankshaft Position Sensor
Fig. 3 Target Magnet
Fig. 4 Target Magnet Polarity
NSIGNITION SYSTEM 8D - 17
DESCRIPTION AND OPERATION (Continued)
CRANKSHAFT POSITION SENSOR
The crankshaft position sensor mounts to the
engine block behind the generator, just behind the oil
filter (Fig. 8).
REMOVAL
(1) Raise and support vehicle.
(2) Disconnect electrical connector from crankshaft
position sensor.
(3) Remove sensor mounting screw.
(4) Pull crankshaft position sensor straight out.
INSTALLATION
NOTE: If the removed sensor is to be reinstalled,
clean off the old spacer on the sensor face. A NEW
SPACER must be attached to the sensor face before
installation. If the sensor is being replaced, confirm
that the paper spacer is attached to the face of the
new sensor.
(1) Install sensor and push sensor down until con-
tact is made. While holding the sensor in this posi-
tion, and install and tighten the retaining bolt to 11.9
N´m (105 in. lbs.) torque.
CAMSHAFT POSITION SENSOR
The camshaft position sensor is mounted to the
rear of the cylinder head (Fig. 9).
REMOVAL
(1) Disconnect the filtered air tube from the throt-
tle body and air cleaner housing. Disconnect the airtube from the oil separator hose. Remove filtered air
tube.
(2) Remove the air cleaner inlet tube.
(3) Disconnect engine harness connector from cam-
shaft position sensor.
(4) Remove camshaft position sensor mounting
screws. Remove sensor.
(5) Loosen screw attaching target magnet to rear
of camshaft (Fig. 10).
INSTALLATION
The target magnet has locating dowels that fit into
off-set machined locating holes in end of the cam-
shaft (Fig. 11).
Fig. 7 Ignition Coil RemovalFig. 8 Crankshaft Position Sensor
Fig. 9 Camshaft Position Sensor Location
NSIGNITION SYSTEM 8D - 19
REMOVAL AND INSTALLATION (Continued)
(5) Test resistance of spark plug cables. Refer to
Group 8D, Ignition System.
(6) Test ignition coils primary and secondary resis-
tance. Replace parts as necessary. Refer to Group 8D,
Ignition System.
(7) Check fuel pump pressure at idle and different
RPM ranges. Refer to Group 14, Fuel System for
Specifications.
(8) The air filter elements should be replaced as
specified in Group 0, Lubrication and Maintenance.
(9) Inspect crankcase ventilation system as out-
lined in Group 25, Emission Control Systems.
(10) Road test vehicle as a final test.
HONING CYLINDER BORES
(1) Used carefully, the cylinder bore resizing hone
C-823 equipped with 220 grit stones, is the best tool
for this job. 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, Tool C-3501,
equipped with 280 grit stones, if the cylinder bore is
straight and round. 20-60 strokes depending on the
bore condition, will be sufficient to provide a satisfac-
tory surface. Inspect cylinder walls after each 20
strokes, using a light honing oil.Do not use engine
or transmission oil, mineral spirits or kerosene.
(3) Honing should be done by moving the hone up
and down fast enough to get a cross-hatch pattern.
When hone marksintersectat 50-60 degrees, the
cross hatch angle is most satisfactory for proper seat-
ing of rings (Fig. 2).(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 50-60
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.
MEASURING MAIN BEARING AND CONNECTING
ROD BEARING CLEARANCES
PLASTIGAGE METHOD
Engine crankshaft bearing clearances can be deter-
mined by use of Plastigage or equivalent. The follow-
ing is the recommended procedure for the use of
Plastigage:
NOTE: The total clearance of the main bearings
can only be determined by removing the weight of
the crankshaft. This can be accomplished by either
of two methods:
PREFERRED METHOD
Shimming the bearings adjacent to the bearing to
be checked in order to remove the clearance between
upper bearing shell and the crankshaft. This can be
accomplished by placing a minimum of 0.254 mm
(0.010 in.) shim (e. g. cardboard, matchbook cover,
etc.) between the bearing shell and the bearing cap
on the adjacent bearings and tightening bolts to
14-20 N´m (10-15 ft. lbs.). The number of main bear-
ing will vary from engine to engine.
Fig. 2 Cylinder Bore Cross-Hatch Pattern
Fig. 3 Plastigage Placed in Lower Shell
NSENGINE 9 - 3
GENERAL INFORMATION (Continued)
CAUTION: Be sure that the tapped holes maintain
the original centerline.
Heli-Coil tools and inserts are readily available
from automotive parts jobbers.
HYDROSTATIC LOCKED ENGINE
When an engine is suspected to be hydrostatically
locked, regardless of what caused the problem, these
steps should be used.
CAUTION: Do Not Use Starter Motor To Rotate
Engine, severe damage may occur.
(1) Inspect air cleaner, induction system and
intake manifold to insure system is dry and clear of
foreign material.
(2) Remove negative battery cable.
(3) Place a shop towel around the spark plugs
when removing them from the engine. This will catch
any fluid that may possibly be in the cylinder under
pressure.
(4) With all spark plugs removed, rotate engine
crankshaft using a breaker bar and socket.
(5) Identify the fluid in the cylinder(s) (i.e., cool-
ant, fuel, oil or other).
(6) Make sure all fluid has been removed from the
cylinders. Inspect engine for damage (i.e., Connecting
Rods, Pistons, Valves etc.)
(7) Repair engine or components as necessary to
prevent this problem from occurring again.
CAUTION: Squirt approximately 1 teaspoon of oil
into cylinders, rotate engine to lubricate the cylin-
der walls to prevent damage on restart.
(8) Install new spark plugs.
(9) Drain engine oil and remove oil filter.
(10) Fill engine with specified amount of approved
oil and install new oil filter.
(11) Connect negative battery cable.
(12) Start engine and check for any leaks.
ENGINE OIL
Checking Oil Level
To assure proper engine lubrication, the engine oil
must be maintained at the correct level. Check the
oil level at regular intervals, such as every fuel stop.
The best time to check the oil level is about 5 min-
utes after a fully warmed-up engine is shut off, or
before starting the vehicle after it has sat overnight.
Checking the oil while the vehicle is on level
ground, will improve the accuracy of the oil level
readings. For 2.4L, 3.3L and 3.8L engines, maintain
the oil level between the MIN and MAX markings on
the dipstick. Adding one quart of oil when the read-ing is at the MIN mark will result in a MAX reading
on these engines. For the 3.0L engine, add one full
quart when the level on the dipstick is at or below
the ADD mark.
ENGINE OIL SERVICE
WARNING: NEW OR USED ENGINE OIL CAN BE
IRRITATING TO THE SKIN. AVOID PROLONGED OR
REPEATED SKIN CONTACT WITH ENGINE OIL.
CONTAMINANTS IN USED ENGINE OIL, CAUSED BY
INTERNAL COMBUSTION, CAN BE HAZARDOUS TO
YOUR HEALTH. THOROUGHLY WASH EXPOSED
SKIN WITH SOAP AND WATER. DO NOT WASH
SKIN WITH GASOLINE, DIESEL FUEL, THINNER, OR
SOLVENTS, HEALTH PROBLEMS CAN RESULT. DO
NOT POLLUTE, DISPOSE OF USED ENGINE OIL
PROPERLY. CONTACT YOUR DEALER OR GOVERN-
MENT AGENCY FOR LOCATION OF COLLECTION
CENTER IN YOUR AREA.
ENGINE OIL SPECIFICATION
CAUTION: Do not use non-detergent or straight
mineral oil when adding or changing crankcase
lubricant. Engine failure can result.
NSENGINE 9 - 5
GENERAL INFORMATION (Continued)
cause of low compression unless some malfunc-
tion is present.
(11) Clean or replace spark plugs as necessary
and adjust gap as specified in Group 8, Electrical.
Tighten to specifications.
(12) Test resistance of spark plug cables. Refer to
Group 8, Electrical Ignition System Secondary Cir-
cuit Inspection.
(13) Test coil output voltage, primary and second-
ary resistance. Replace parts as necessary. Refer to
Group 8, Electrical Ignition System.
(14) Check fuel pump pressure at idle and differ-
ent RPM ranges. Refer to Group 14, Fuel System for
Specifications.
(15) The air filter elements should be replaced as
specified in Group 0, Lubrication and Maintenance,.
(16) Inspect crankcase ventilation system as out
lined in Group 0, Lubrication and Maintenance. For
emission controls see Group 25, Emission Controls
for service procedures.
(17) Inspect and adjust accessory belt drives refer-
ring to Group 7, Cooling System, Accessory Drive
Belts for proper adjustments.
(18) Road test vehicle as a final test.
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 RADIATOR 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 radiator 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 and 552 kPa (80 psi) recom-
mended.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 radiator coolant.
All gauge pressure indications should be equal,
with no more than 25% leakage.
FOR EXAMPLE:At 552 kPa (80 psi) input pres-
sure, a minimum of 414 kPa (60 psi) should be main-
tained in the cylinder.
LASH ADJUSTER (TAPPET) NOISE DIAGNOSIS
A tappet-like noise may be produced from several
items. Check the following items.
(1) Engine oil level too high or too low. This may
cause aerated oil to enter the adjusters and cause
them to be spongy.
(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 pressed into 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 disassem-
bleDo not reuse retainer caps. Do not inter-
change parts and make sure that care and
cleanliness is exercised in the handling of parts.
c. Clean out dirt and varnish with solvent.
d. Reassemble with engine oil.
e. Check for sponginess.
f. If still spongy, replace with new adjuster.
INSPECTION (ENGINE OIL LEAKS IN GENERAL)
Begin with a through visual inspection of the
engine, particularly at the area of the suspected leak.
If an oil leak source is not readily identifiable, the
following steps should be followed:
(1) Do not clean or degrease the engine at this
time because some solvents may cause rubber to
swell, temporarily stopping the leak.
9 - 8 ENGINENS
DIAGNOSIS AND TESTING (Continued)