Porsche 928 1982 Owner's Manual page 63

To avoid damage to the engine, only add
cold anti-freeze and cold water to the cool-
ing system when the engine is also cold.
A warm engine should only be topped up if
the coolant level has dropped appreciably
below the filler mark. Too much added cool-
ant will escape through the pressure cap
when coolant warms up.
Bleeding cooling system
If more than about 1.1 U.S. qt. or 1 liter must
be added, the cooling system should be bled.
1 - move the temperature control lever (up-
per lever) in the center console all the
way to the right.
2 - start the engine and allow it to run at in-
creased idle for about one minute
3 - turn the engine off
4 - r e c h e c k the coolant level and add as
necessary.
For anti-freeze/water mixing ratios and
cooling system capacity, see "Winter
Operation" and "Filling Capacities", re-
spectively.
Changing coolant
(with cold engine only)
1 - move temperature control lever at all the
way to the right. On vehicles equipped with
an automatic climate control system, also
turn on the ignition, leaving key in position
" 2 " for about 1 minute. Then turn ignition
off.
2 - remove filler cap from expansion tank
3 - unscrew and remove drain plug (arrow)
from radiator and drain coolant
4 - unscrew and remove drain plugs (arrow)
from left and right hand sides of crank-
case and drain coolant
5- replace seals for drain plugs on crank-
case and the O-ring for drain plug on
radiator.
Tightening torques:
- radiator plug:
1.1-1.5 Ibft or 1.5-2.0 Nm
- crankcase drain plugs:
3 3 - 3 7 Ibft or 4 5 - 5 0 Nm
6 - add coolant until level reaches edge of
filler cap opening (with heater lever set
at "warm")
7 - run engine at increased idle until it reach-
es operating temperature and recheck
coolant level
8 - coolant level should be in the middle of
expansion tank.
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