DESCRIPTION
The basic liquid cooling system consists of a radiator, water pump, thermostat, cooling fan, pressure cap, heater (if equipped), and various connecting hoses and cooling passages in the block and cylinder head. In addition, many cars use a fan clutch (incorporating a thermostatic control) or flexible fan blade. These reduce noise and power requirements at higher engine speeds.
Some models may use a thermostatic vacuum switch to advance ignition timing in the event of overheating. Most models use a coolant recovery system to prevent loss of anti-freeze.
DRAINING & FILLING COOLANT SYSTEM
- Disconnect the negative (-) battery cable, remove the expansion tank cap, and set the temperature control knob in the passenger compartment to warm.
- Loosen the radiator drain plug at the bottom of the radiator next to the battery. (Scheme 1)
- Remove the engine block drain plug. (Scheme 2) The drain plug is located behind the exhaust manifold.
- Reinstall the drain plugs using new gaskets. Tighten engine block drain plug to 15 N.m (11 ft. lbs.).
- With the engine off, open the bleeder screw on the thermostat housing. (Scheme 3) 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. See «COOLING SYSTEM SPECIFICATIONS»(/saab/900/i-1978-1994/remont/cooling-system-mechanical/#cooling-system-specifications).
| CAUTION | Always use Saab original coolant or equivalent to avoid the formation of harmful, clogging deposits in the cooling system. Use of other anti-freeze solutions may be harmful to the cooling system. The final coolant level is best checked when the cooling system is fully cold. DO NOT reuse the coolant when replacing damaged engine parts. Contaminated coolant may damage the engine or cooling system. If coolant comes in contact with paint or bodywork rinse with water. Coolant will damage paint. |
Scheme 1
Scheme 2
Scheme 3
TEMPERATURE GAUGE QUICK-CHECK
A quick-check of the coolant temperature sender can be made to determine the cause of an incorrectly reading temperature gauge. The checks should be made at the coolant temperature sender on the front of the cylinder head, below the distributor. (Scheme 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. See COOLING SYSTEM SPECIFICATIONS .
Note. When replacing a faulty coolant temperature sender, drain the cooling system below the level of the sender and then unscrew the sender.
Scheme 4
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.
| Application | Specification | |
|---|---|---|
| Coolant Type | Phosphate-free 50% mixture anti-freeze 50% water | |
| Coolant Replacement Interval | (1) 30,000 Miles | |
| Permissible Coolant Leakage | 1 qt. over 60,000 miles (1 liter/100,000 km) | |
| Coolant Temperature Sender Resistance at 90°C (194°F) | 46.9-55.5 ohms | |
| Coolant Thermoswitch | ||
| Closing Temperature | 194-203°F (90-95°C) | |
| Opening Temperature | 185-194°F (85-90°C) | |
| Cooling System Capacity | ||
| 900 Model | 10 liters (10.5 qts.) | |
| 9000 Model | 8.65 liters (9.10 qts.) | |
| Cooling System Test Pressure | (2) 0.9-1.2 bar (13.0-17.4) | |
| (1) Interval is for first service. Change every 15,000 miles thereafter. (2) Expansion tank relief valve will open in this range. | ||
| (1) | Interval is for first service. Change every 15,000 miles thereafter. |
| (2) | Expansion tank relief valve will open in this range. |
COOLING SYSTEM SPECIFICATIONS
See also:
• COOLING SYSTEM SPECIFICATIONS