Pontiac 2007 Solstice - Manual (Page 267)

3. Fill the coolant surge tank with the proper
mixture, to the COLD FILL line. Wait about
five minutes, then check to see if the level is
below the COLD FILL line. If the level is
below the line, add additional coolant to bring
the level up to the line. Repeat this procedure
until the level remains constant at the
COLD FILL line for at least five minutes.
4. With the coolant surge tank pressure cap off,
start the engine and let it run until you can
feel the upper radiator hose getting hot.
Watch out for the engine cooling fan.
By this time, the coolant level inside the
coolant surge tank may be lower. If the level
is lower than the COLD FILL line, add more of
the proper mixture to the coolant surge tank
until the level reaches the COLD FILL line.
5. Then replace the pressure cap. Be sure the
pressure cap is hand-tight and fully seated.
See your dealer, if necessary.
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