Chevrolet Trailblazer 2023 Owner's Manual page 254

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 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
mixture to the coolant surge tank until
the level reaches the indicated
level mark.
5. Replace the pressure cap tightly.
Vehicle Care
6. Verify coolant level after the engine is
shut off and the coolant is cold.
If necessary, repeat coolant fill procedure
Steps 1 6.
If the coolant still is not at the proper
level when the system cools down again,
see your dealer.
Caution
If the pressure cap is not tightly installed,
coolant loss and engine damage may
occur. Be sure the cap is properly and
tightly secured.
Automatic Coolant Service Fill Instruction
If equipped, this feature assists in filling and
removing air from the cooling system after
service of components or when coolant is
added after being too low.
To activate the fill and air removal process:
1. With a cold system, open the surge tank
cap and add coolant to the indicated
mark on the surge tank.
2. Connect the vehicle to a battery charger.
3. Turn the ignition to Service Mode. See
Ignition Positions (Key Access) 0 184 or
Ignition Positions (Keyless Access) 0 186.
4. Turn off the air conditioning.
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