Saab 1987 900 - Braking System Guidance

54 Car care and scheduled maintenance
Filling
1. Close the drain cock and plug and ensure
that the heater control is set to max-
imum heat.
2. Fill the system with coolant until the
expansion tank is filled.
3. Open the bleeder nipple on the thermos-
tat housing, allow the coolant to flow
out of the nipple until free from air bub-
bles.
4. Close
the bleeder nipple, top up the
expansion tank if necessary and replace
cap.
Anti-freeze coolant mixtures
The cooling system is factory filled with a
mixture of ethylene glycol and water (50- 50
mix). For maximum security against fre-
ezing and corrosion the glycol should be 50 -
70%
ofthe mixture. Always use Saab brand
anti-freeze, which is suitable for engines
with aluminum alloy cylinder heads, and
mix with clean fresh water (see below).
To prevent freezing in the cold season and
reduce the risk of boiling over in hot wea -
ther, never use pure water in the cooling
syst em. Pure water is also undesirable as it
affords no corrosion protection.
The factory fill coolant must be changed
and the system flushed according to the
maintenance schedule as the important
corrosion inhibitors and other coolant addi-
tives lose their effectiveness with time and
use. Without adequate corrosion protec-
tion, serious damage may occur to the
cylinder head and other components in
contact with the coolant. Corrosion protec-
tion may be depleted even though the coo-
lant gives adequate anti-freeze protection
and has an acceptable (alkaline) pH level of
7.5-11. When preparing a new coolant solu-
tion, mix the recommended ethylene glycol
with water low in corrosive irons such as
chlorides and sulfates . Avoid hard water
which can cause clogging in the radiator.
Do not use coolant booster additives. Keep
the cooling system full and free of air pock -
ets and foaming .
Saab brand coolant (BASF G-105) meets
Factory recommendations and is available
at Saab dealers.
NOTE! When topping up the system,
premix the ethylene glycol with a suita-
ble quantity of water. As full circulation
cannot take place until the thermostat
opens, there is still a risk of the engine
being damaged by ice if the glycol and
water were added separately and did not
mix quickly enough.
Thermostat
A special 3-way thermostat is used. Ope-
ning temperature specifications are as fol-
lows:
Naturally aspirated engines -
Standard, 88 °C
Hot weather alternate, 82 °C
Extreme cold weather, 92 °C
(Do not use in Turbo engines)
Turbocharged engines-
Standard,82°C
Extreme cold weather, 88 °C
Brakes
The footbrake system is power-assisted,
with the result that the force applied to the
brake pedal is amplified on braking. Howe-
ver, this additional power is on ly available
when the engine is running. Much greater
pressure on the brake peda l will be needed
to brake the car when the engine is swit-
ched off.
There are two warning lights on the instru-
ment panel, one for the handbrake and one