Page 181
Exhaust Emission Control
EXHAUST GAS RECIRCULATION
SYSTEM (EGR)
The exhaust gas recirculation system functions to recirculate a small amount of the exhaust gases into the intake manifold. This lowers combustion chamber temperatures and
reduces exhaust emissions.
254-3
NOTE
• If a fault occurs in the EGR system, the Check Engine light
will come on and a fault code will be stored in the memory of
the LH control unit.
• On cars equipped with the electronic EGR system, the
Check Engine light may come on intermittently, even though
there are no emissions or fuel system-related faults. To remedy this problem, a special wiring hamess has been made. See
an authorized Saab dealer for additional information.
Electronic EGR System (1990 and later
Californian and SPG models only)
To test EGR valve
This electronic system is controlled by the LH control unit
and uses engine temperature, engine load, and road speed
inputs to determine the optimum amount of EGR needed. The
main components of the system are the valve, the temperature
sensor, and the modulating valve. See Fig. 5
I Jt-eJ-------------
The EG R valve is shown in Fig. 6.
5
-------,31 4
I
2
):ii::':::=:::;~=:-
1
'
6
9
87958
1. LH control unit
2. EGR valve
3. Temperature sensor (NTC)
4. EGR pipe
5 Modulating valve
6.
7.
8.
9.
10.
Intake manifold
Vacuum tank
Check valve
Exhaust manifold
Overflow valve (turbo only)
Fig. 6. EGR valve on underside of intake manifold. Temperature
sensor shown at arrow,
i
Fig. 5. Schematic of Electronic EGR system and hose routing.
The LH control unit sends a signal to the modulating valve,
which allows engine vacuum to open the EGR valve. The temperature sensor, which is mounted to the EGR valve, monitors
when the valve is open and closed. When troubleshooting the
EGR system, check that all hoses are properly connected.
Check the hoses for cracks or deterioration. Check the wiring
to the EGR modulating valve and the temperature sensor for
any visible damage.
1. Start and run the engine until it is at operating temperature. Disconnect the hose leading to the EG R valve.
2. Apply vacuum to the disconnected hose. Use a handheld vacuum pump or suck on the end of the hose to
create the vacuum. The engine idle speed should drop
noticeably, and the engine may even stall. Reconnect
the hose to the EGR valve.
If any faults are found, remove and clean the EGR valve. Be
sure to also clean the EGR valve opening in the bottom of the
intake manifold. Install the EG R valve and recheck. If any
faults are found, the EGR valve should be replaced.
EXHAUST GAS RECIRCULA nON SYSTEM (EGR)
Page 182
254-4
Exhaust Emission Control
To test modulating valve and signal to
modulating valve
The EGR modulating valve is mountedto the driver's side of
the fender. See Fig. 7.
87967
~-----------Fig. 8.
4
To test EGR temperature sensor
~
Fig. 7.
EGR modulating valve.
1. Disconnect the connector from the modulating valve.
Check the electrical resistance of the valve with an
ohmmeter or apply battery voltage to the valve's terminals. The valve should audibly click when voltage is applied. If the resistance is not as specified or the valve
doesn't click, it should be replaced.
EGR modulating valve
• valve resistance
approximately 30 ohms
NOTE
It may be easier to apply voltage to the valve by first removing
it from its mountings.
2. Connect an LED test light or a fuel injector test light to
the valve's harness connector. See Fig. 8.
3. Start and run the engine until it is at operating temperature.
4. Raise the idle speed above 2500 rpm. The LED should
flicker.
EXHAUST GAS RECIRCULA nON SYSTEM (EGR)
LED test light connected to modulating valve connector.
If the light does not I1icker as described above, turn the engine off and check for power at pin 1 of the connector with the
ignition key on. IJ battery voltage is not present, check for wiring faults to the valve using the appropriate wiring diagram
shown in 371 Wiring Diagrams, Fuses and Relays. If battery
voltage is present, check for continuity in the wire between the
valve and the LH control unit (pin 19). If no wiring faults can be
found, the LH control unit may be faulty.
1. to EGR valve
2. to Intake manifold via vacuum tank
3. Turbo: to air hose between air mass meter and turbocharger
Non-turbo: to air hose between air mass meter and throttle
housing
4. Two pin connector (signal from LH control unit)
L~
I
1. With the engine cold, disconnect the 2-pin connector
from the temperature sensor on the EGR valve (see
Fig. 6 shown above). Connect an ohmmeter to the sensor terminals. Check that there are several megohms of
resistance.
2. Run the engine at speeds above 2500 rpm. After a
short period, the sensor's resistance should gradually
drop to several thousand ohms or less as the EGR
valve heats up.
If the EGR temperature sensor does not respond as specified, it should be replaced. Be sure to checkfor a good ground
at pin 2 (black wire) of the sensor.
Page 183
--Radiator and Cooling System
261-1
261 Radiator and Cooling System
General.
Coolant Pump and Thermostat.
Radiator and Expansion Tank
Radiator Cooling Fans
Warnings and Cautions
Troubleshooting
Pressure Test
Temperature Gauge Quick-Check
Radiator Fan Quick-Check
Thermostat Quick-Check
Coolant and Hoses
To drain and fill cooling system
261-1
261-1
261-1
261-1
261-2
261-3
261-3
261-4
261-4
261-5
261-5
261-5
GENERAL
This section covers repairs and troubleshooting information
for the engine cooling system only. For heater core and related heating and air conditioning components, see 854 Heating
and Air Conditioning. For information on the engine oil cooler used on turbo models, see 220 Lubrication System. For
information on the ATF cooler used on models with automatic
transmission, see 4 TRANSMISSION.
Additional cooling system components and accessories,
such as a winter thermostat for extremely cold climates, an air
diverter for extra air flow across the radiator for warm climates, and engine block heaters for easier winter starting, are
available through an authorized Saab dealer. Check with your
authorized dealer for application and availability information.
Fig. 1 is a schematic view of the cooling system.
Coolant Pump and Thermostat
The coolant pump is crankshaft-driven by a V-belt. A threestage thermostat controls the flow of coolant. When the engine is cold the thermostat is closed and coolant bypasses the
radiator to circulate coolant through the engine and heater
core only. When the engine warms up, the thermostat opens
and coolant circulates through the complete system. When
To replace a hose
Thermostat.
To replace thermostat
Coolant Pump
To replace coolant pump
Radiator and Cooling Fans
To remove radiator
To replace radiator
cooling fan thermoswitches
To remove radiator cooling fans
261-6
261-6
261-6
261-7
261-7
261-8
261-8
261-8
261-9
the engine reaches full operating temperature, the thermostat
closes off the lower outlet in the thermostat housing to substantially reduce the coolant flow through the heater core. See
Fig.2.
NOTE
On certain 1985 through 1989 models, the heater core may
not receive suHicient coolant flow at low engine speeds during
stop-and-go driving in cold weather. If low heater output is experienced during these conditions only, see 854 Heating and
Air Conditioning for information on installing a special circulation pump.
Radiator and Expansion Tank
The radiator is a crossflow design. A translucent expansion
tank, or overflow reservoir provides for coolant expansion at
higher temperatures and easy monitoring of coolant level.
Radiator Cooling Fans
The cooling fans are mounted to the radiator and are electrically operated. The main fan is switched on and off via a coolant thermoswitch. The main fan also runs whenever the NC
GENERAL
Page 184
261--2
Radiator and Cooling System
1
7
"==~o 8
..
Hot water
¢
Cold water
6
1. Radiator
2. Coolant pump
3. Thermostat housing
4. Preheater, intake manifold
5. Heater valve in open position
6. Heater valve in closed position
87224-S21372
7. Heater core
8. Coolant expansion tank
Fig. 1. Schematic view of cooling system.
switch is on. The auxiliary cooling fan runs anytime the NC
compressor is cycling.
Warnings and Cautions
The following warnings and cautions should be followed
when working on the cooling system.
2
WARNING
• At normal operating temperature the cooling system is pressurized. Allow the system to cool as long as possible before
opening---a minimum of an hour-then release the cap very
slowly to allow safe release of pressure.
4
• Releasing the cooling system pressure lowers the coolant's
boiling point, and the coolant may boil suddenly. Use heavy
gloves and wear eye and face protection to guard against
scalding.
• Use extreme care when draining and disposing of engine
coolant. Coolant is poisonous and lethal to pets. Pets are attracted to coolant because of its sweet smell and taste. See a
veterinarian immediately if any amount of coolant is ingested
by the animal.
GENERAL
87225-S2371
1. to Radiator
2. From engine block/cylinder head
3. to Heater
4. By-pass port
Fig. 2. Schematic view of three-way thermostat
Page 185
Radiator and Cooling System
261-3
CAUTION
WARNING
Avoid a~ding cold water to the coolant while the engine is hot
or overheated. If it is necessary to add coolant to a hot system,
do so only with the engine running and coolant pump turning.
Be careful when working near the cooling fans when the engine is hot. The fan can come on at anytime-even if the ignition key is oft.
TROUBLESHOOTING
When investigating the cause of overheating or coolant
loss, begin with a visual inspection of the system. Carefully
check for a broken or loose coolant pump V-belt. Check the
coolant level and check for evidence of coolant leaks.
Check that the radiator fins are not blocked with dirt or debris. Clean the radiator fins using low-pressure water or compressed air. Blowfrom the engine side out.
Inspect the coolant pump by first removing the V-belt from
the pump. Firmly grasp opposite sides of the pulley and check
for play in all directions. Rotate the pulley and check that the
shaft runs smoothly. If any faults are found the pump should
be replaced.
NOTE
The coolant provides some lubrication for the pump shaft, so
an occasional drop of coolant leaking from the pump is acceptable. If coolant drips from the vent hole, the pump should
be replaced.
Most cooling system faults can be grouped into one of three
main categories: 1) cooling system leaks, 2) poor coolant circulation, or 3) radiator cooling fan electrical faults.
The cooling system becomes pressurized at normal operating temperature, which raises the boiling point of the coolant.
Leaks may prevent the system from becoming pressurized,
allowing the coolant to boil at a lower temperature. If visual evidence is inconclusive, a cooling system pressure test, as described below, will help to pin point hard to find leaks.
If the cooling system is full of coolant and holds pressure,
the next most probable cause of overheating is the result of
poor coolant circulation due to a failed thermostat or coolant
pump, a pinched or restricted hose, or a clogged system.
To quickly check if the thermostat is opening and if coolant
is circulating through the radiator, allow a cold engine to reach
operating temperature (temperature gauge needle approximately centered). Feel the radiator hoses. If the hoses are hot
to the touch, the coolant is probably circulating correctly. If
there are any cool areas in the hoses or radiator, coolant flow
to the radiator is restricted. Check for a faulty thermostat or a
plugged radiator.
NOTE
A thennostat that is stuck open will cause the engine to wann
up slowly and run below nonnal temperature at highway
speed. A thennostat that is stuck closed will restrict coolant
flow to the radiator and cause overheating.
An otherwise sound cooling system will overheat if the electric cooling fans are not operating correctly. The fans should
switch on and off according to engine coolant temperature or
whenever the AlC is on. Below are a few quick checks to help
diagnose cooling system faults.
If the engine overheats and no other cooling system tests
indicate trouble, the radiator may have some plugged passages that are restricting coolant flow. This does not necessarily
mean that the radiator must be replaced. In many cases the
radiator can be chemically cleaned by a qualified radiator repair shop.
Pressure Test
A pressure test uses a special tester to pressurize the system and simulate normal running conditions. If the system is
unable to hold pressure, the engine will overheat more easily.
Aside from locating external leaks, a pressure test can be
used to checkfor internal leaks. Some of the common sources
of internal leaks are a faulty cylinder head gasket, a cracked
cylinder head, or a cracked cylinder block.
Requirements:
• cooling system pressure tester
• engine warm
With the engine at normal operating temperature, pressurize the system. See Fig. 3. Loss of pressure indicates leaks
that may also be detected by the seepage of coolant. If the
pressure drops rapidly and there is no sign of coolant leakage,
the cylinder head gasket may be faulty. See 211 Cylinder
Head Removal and Installation for gasket replacement procedures.
The screw-on type expansion tank cap should also be tested using a pressure tester and the correct tester adapter.
Carefully inspect the cap for damage. A faulty cap or a damaged cap gasket should be replaced.
TROUBLESHOOTING
Page 186
261-4
Radiator and Cooling System
Cooling system test pressures
• Maximum system pressure
1.2 bar (17.5 psi)
• Expansion tank cap
opening pressure .... 0.9 to 1.2 bar (13 to 17.5 psi)
CAUTION
Exceeding the specified test pressure could damage the radiator or other cooling system components.
Fig. 4. Coolant temperature sender (arrow) below distributor on front
of cylinder head,
When replacing a faulty coolant temperature sender, drain
the cooling system down below the level of the sender and
then unscrew the sender.
Radiator Fan Quick-Check
If the main fan does not come on, a quick-check can be
made to determine whether the fault is in the fan, the thermoswitch, or the fan's electrical circurt. Be sure to check fuse no.
25 (30 amp) and fuse no. 6 (30 amp) before making any tests.
Fig. 3. Cooling system being checked for leaks using pressure
tester.
To test the fan, turn the ignition on and remove the rubber
boot from the fan's thermoswitch on the left side of the radiator. Using a screwdriver, short the two switch terminals together and check that the fan runs. See Fig. 5.
Temperature Gauge Quick-Check
A quick-check of the coolant temperature sender can be
made to determine the cause of a faulty coolant temperature
gauge. The checks should be made at the coolant temperature sender on the front of the cylinder head, below the distributor. See Fig. 4.
Disconnect the wire from the sender and hold it to ground.
Turn the ignition on. If the gauge needle moves upward, the
sending unit is faulty. If the gauge does not respond, the wiring
to the gauge is broken (open circuit) or the gauge itself is
faulty. To check the resistance of the sender measure between ground and the sender terminal with the wire disconnected.
Coolant temperature sender specification
• sender resistance at 90°C (194°F) ... 51 .2±4.3 ohms
Fig. 5. Main cooling fan thermoswitch being shorted using
screwdriver,
If the fan runs only when the switch is bypassed, the thermoswitch is faulty and should be replaced. If the fan does not
TROUBLESHOOTING
Page 187
Radiator and Cooling System
261-5
run, check for battery voltage between the green wire and
ground at the thermoswitch. If voltage is present, the fan is
faulty and should be replaced. If voltage is not present, check
the wiring and the fan relay using the diagrams shown in 371
Wiring Digrams, Fuses and Relays. Additional information
on replacing the thermoswitch and the radiator cooling fan is
given below.
NOTE
The auxiliary fan located beside the main fan on the radiator
is part of the Ale system. See 8 BODY for additional information on this fan.
Thermostat Quick-Check
To quickly check if the thermostat is opening and if coolant
is circulating through the radiator, allow a cold engine to reach
operating temperature (temperature gauge needle approximately centered). Feel the radiator hoses. If the hoses are hot
to the touch, the coolant is circulating. If the hoses are not hot,
coolant flow to the radiator is restricted. Check for a faulty
thermostat or a plugged radiator.
Fig. 7. Cylinder block showing location of coolant drain plug 2, Do
not remove cover 1 or plug 3.
4. Reinstall the drain plugs using new gaskets.
COOLANT AND HOSES
To drain and fill cooling system
1. Disconnect the negative (-) battery cable, remove the
expansion tank cap, and set the temperature control
knob in the passenger compartment to warm.
2. Loosen the radiator drain plug at the bottom of the radiator next to the battery. See Fig. 6.
Tightening torque
• Engine block drain plug
(with new gasket)
15 Nm (11 ft-Ib)
5. With the engine off, open the bleeder screw on the thermostat housing. See Fig. 8. Using a coolant mixture of
50% anti-freeze and 50% water, fill the expansion tank
slowly so that air is allowed to escape. Close the bleeder screw when coolant begins to come out of the bleeder. Run the engine and check for leaks.
Cooling system capacity
• 10 liters (10.5 qts.)
Fig. 6. Radiator drain plug (arrow).
87936
3. Remove the engine block drain plug. See Fig. 7. The
drain plug is located behind the exhaust manifold.
Fig. 8. Exploded veiw of thermostat housing and bleeder screw (arrow). 16 valve model shown,
COOLANT AND HOSES
Page 188
261-6
Radiator and Cooling System
~~-------l
CAUTION
• Always use Saab original coolant to avoid the fonnation of
hannful, clogging deposits in the cooling system. Use of other
anti-freeze solutions may be harmful to the cooling system.
I
I
I
f--- Connection
,I
• The fin.al coolant level is best checked when the cooling system is fully cold.
• _.J
• Do not reuse the coolant when replacing damaged engine
parts. Contaminated coolant may damage the engine or cooling system.
Hose
7233
• If coolant comes in contact with paint or bodywork rinse with
water. Coolant will damage paint.
Fig. 10. Hose clamp correctly installed on hose end.
To replace a hose
1. Drain the coolant as described above.
2. Remove the hose. Using a screwdriver, loosen each hose
clamp and slide the clamps away 'from the hose ends.
NOTE
If a radiator hose is stuck to the radiator connection, cut the
old hose off the connection as shown in Fig. 9. Prying the hose
loose may damage the connection or the radiator.
------I
CAUTION
Do not overtighten clamps. Tighten Just enough to seal. Overtightening may damage the hose and cause premature failure.
6. Refill and bleed the radiator as described above. Run
the engine until warm. Check for leaks.
THERMOSTAT
To replace thermostat
1. Drain the coolant as described above.
2. Remove the thermostat housing bolts. Remove the
housing and thermostat. See Fig. 8 above.
3. Position the new thermostat and gasket in the outlet.
Install the thermostat housing.
Tightening torque
• thermostat housing
to cylinder head
18 Nm (13 ft-Ib)
7232
Fig. 9. Stuck hose being removed by cutting.
3. Clean the hose connections and remove any bits of old
hose and sealer.
4. Install the new hose. Slide the loose clamps over the
hose and slide the hose ends over the connections.
5. Position and tighten the clamps. Place the clamp as
near the bead as possible and at least 4 mm (5/32 in.)
from the hose end, as shown in Fig. 10. Tighten the
clamps enough to compress the hose firmly around the
connections.
THERMOSTAT
CAUTION
Saab uses a special three stage thennostat. When replacing,
be sure to use only an original Saab part. The engine should
not be operated without a thennostat.
4. Refill and bleed the cooling system.
Page 189
Radiator and Cooling System
261-7
COOLANT PUMP
Fig. 11 is an exploded view of the coolant pump. Always
plan to replace gaskets and seals and to have them on hand
before beginning repairs.
Bracket -----'\_
1I-Io_-~..----Coolant
To replace coolant pump
oullet
1. Disconnect the negative (-) battery cable.
2. Drain the cooling system as described above.
Gasket------4G
Case
Coolant
pump
Pulley - - - - - - 1
87234·52/11 11
Fig. 11. Coolant pump exploded view.
3. Loosen the four bolts securing the pulley to the pump.
4. Remove the V-belts from the pump as described in 1
LUBRICATION AND MAINTENANCE. Then remove
the pulley mounting bolts and the pulley. See Fig. 12.
5. Remove the coolant pump bolts and remove the coolant pump from the case. See Fig. 13. Note the position
of the two longer bolts.
Installation is the reverse of removal. Clean the pump matIng surface before installing a new gasket. Install the V-belts
as described in 1 LUBRICATION AND MAINTENANCE. Fill
and bleed the cooling system as described above. Start the
engine and check for leaks.
Fig. 12. Coolant pump pulley being removed.
THERMOSTAT
Page 190
261-8
Radiator and Cooling System
87237-S/2402
Fig. 13. Coolant pump being removed.
Fig. 14. Radiator mounting screw being removed. Also remove screw
(arrow) on other side. Tilt radiator back to remove.
RADIATOR AND COOLING FANS
Replacement radiators from Saab may not fit into some of
1989 and early cars without installing a special radiator
mounting kit and making some minor modifications. See your
Saab dealer for details.
To remove radiator
1. Disconnect the negative (-) battery cable. Disconnect
the harness connectors from the fans, the ground
straps, and the thermoswitch wires.
2. Drain the cooling system as described above. Disconnect all coolant hoses from the radiator.
3. Remove the air filter intake shroud and the distributor
cap.
4. Remove the two bolts securing the radiator and remove the radiator and cooling fans as an assembly.
See Fig. 14.
5. Working at the bench, remove the fan assemblies and
any other hardware.
Installation is the reverse of removal. Inspect the rubber
lower radiator mountings and replace any that are damaged.
Fill and bleed the cooling system as described above.
RADIA TOR AND COOLING FANS
To replace radiator cooling fan thermoswitch
1. Disconnect the negative (-) battery cable.
2. Drain the cooling system as described earlier.
3. Disconnect the wires from the thermoswitch and unscrew the switch. Install the new switch. See Fig. 15.
NOTE
• Always the replace the sealing ring when installing a new
thennoswitch.
• To test the thennoswitch, heat it in a pan of water with an
ohmmeter connected to it tenninals. Check the temperature of
the water when the switch closes.
Radiator Cooling Fan Thermoswitch
• closes (fan on)
• opens (fan off)
194-203°F (90-95°C)
185-194°F (85-90°C)
4. Fill and bleed the cooling system. Start the engine and
check for leaks. Always verify that both fans operate by
allowing the engine to run at temperature and by
switching on the NC.