Pontiac Sunbird Owner's Manual page 176

.
Start the engine and let it
run
until
you can feel the upper radiator hose
getting hot. Watch out for the engine
fan.
.
By this time, the coolant level inside
the thermostat housing filler neck
may be lower. If the level is lower,
,
add more of the proper
mix through
the filler neck until the level reaches
1
the base of the filler neck.
9. Replace the thermostat, making sure
it is properly inserted, then replace
the pressure cap. Be sure the arrows
on the pressure cap line up like this.
How to Add Coolant to the 3.lL V6
Engine at the Coolant Surge
lhk:
1. You can remove the coolant surge
tank
pressure cap when the cooling
system, including the coolant surge
t a n k pressure cap and upper radiator
hose, is no longer hot. Turn the
pressure cap slowly to the left until it
first stops. (Don't press down while
turning the pressure cap.)
If you hear a hiss, wait for that to stop.
A hiss means there is still some pressure
left.
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