Saab 900 1983 - Page 26

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4. Open engine drain plug lo cated to the right
of the engine, under the exhaust manifold.
Filling
1. Close the drain cock and plug and ensure
t
hat the heater control is set to maximum
heat.
2.
Fill the system with coolant until the expan·
sion tank Is filled.
3. Open the bleeder nipple on the thermostat
housing, allow the coolant to flow out of the
nipple until free from air bubbles .
4.
Close the bleeder nipple. top up the expan·
sion tank if necessary and replace cap.
Anti·Freeze Coolant Mixtures
The cooling system is factory filled with a mix·
ture of ethylene glycol and water (50·50 mix). For
maximum security against freezing and corro·
sion the glycol should be 50·70% of the mixture.
Use
low phosphate anti· freeze brands suitable
for engines with aluminum alloy cylinder heads
and
mix with clean fresh water (see below).
To prevent freezing in the cold season and reo
duce the risk of boiling over in hot weather,
never use pure
water in the cooling system.
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 main·
tenance schedule as the important corrosion
inhibitors and other coolant additives lose their
effectiveness with time and use. Without ade·
quate corrosion protection, serious damage
may
occur to the cylinder head and other com·
ponents In contact with the coolant. Corrosion
protection may be depleted even though the
coolant gives adequate anti·freeze protection
and has an acceptable (alkaline) pH level of 7.5·
11 . When preparing a new coolant solution, mix
the recommended ethylene glycol with water
low in corrosive ions such as chlorides and sui·
fates. Avoid hard water which can cause clog·
ging in the radiator . Do not use coolant booster
additives . Keep the cooling system full and free
of air
pockets and foaming.
NOTE! When topping up the system, pre·
mix the ethylene glycol with a suitable
quantity of water. As full circulation can·
not take place until the thermostat
opens . there Is stili 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. The stan·
dard opening temperature is BBoC . Optional
thermostats are available as follows :
Hot weather : B2°C calibration
Extreme cold weather : 92°C calibration (Do
not use on Turbo engines).
f