Cadillac 2014 ATS Owner's Manual page 306

surge tank pressure cap and
upper radiator hose, is no
longer hot.
Turn the pressure cap slowly
counterclockwise. 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. Open the
surge tank service port cap to
the lower chamber
3. Fill the surge tank top chamber
with the proper DEX-COOL
coolant mixture to the bottom of
the fill neck. The top chamber
needs to be completely full. Fill
the surge tank bottom chamber
through the service port to
approximately half.
4. With the coolant surge tank
pressure cap off and the surge
tank service port cap open, 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 top
chamber may be lower. If the
level is lower, add more of the
proper DEX-COOL coolant
mixture to the surge tank top
chamber until the level reaches
the bottom of the fill neck.
5. Replace the surge tank pressure
cap tightly and close the surge
tank service port cap.
If the pressure cap is not tightly
installed, coolant loss and
possible engine damage may
occur. Be sure the cap is properly
and tightly secured.
Check the level in the surge tank
top and bottom chambers when the
cooling system has cooled down.
If the coolant is not at the proper
levels, repeat Steps 1 3 and
reinstall the pressure cap and close
the service port. If the coolant still is
not at the proper levels when the
system cools down again, see your
dealer.
The vehicle has an indicator to warn
of the engine overheating.
If the decision is made not to lift the
hood when this warning appears,
get service help right away. See
If the decision is made to lift the
hood, make sure the vehicle is
parked on a level surface.
Then check to see if the engine
cooling fan is running. If the engine
is overheating, the fan should be
running. If it is not, do not continue
to run the engine. Have the vehicle
serviced.
.