Chevrolet 2012 Sonic Owner's Manual page 228

10-18 Vehicle Care
WARNING
You can be burned if you spill
coolant on hot engine parts.
Coolant contains ethylene glycol
and it will burn if the engine parts
are hot enough. Do not spill
coolant on a hot engine.
1.4L Engine Shown, 1.8L Engine
Similar
1. Remove the coolant surge tank
pressure cap when the cooling
system, including the coolant
surge tank pressure cap and
upper radiator hose, is no
longer hot.
Turn the pressure cap slowly
counterclockwise about
one-quarter of a turn. If you
hear a hiss, wait for that to stop.
This will allow any pressure
still left to be vented out the
discharge hose.
2. Keep turning the pressure cap
slowly and remove it.
3. Fill the coolant surge tank with
the proper DEX-COOL coolant
mixture to the indicated
level mark.
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, add more of the proper
DEX-COOL coolant mixture to
the coolant surge tank until the
level reaches the indicated
level mark.
5. Replace the pressure cap. Be
sure the pressure cap is
hand-tight.
Check the level in the coolant
surge tank when the cooling system
has cooled down. If the coolant is
not at the proper level, repeat
Steps 1 3 and reinstall the pressure
cap. If the coolant still is not at the
proper level when the system cools
down again, see your dealer.