GMC Cadillac CT5 2021 Manual page 325

324 VEHICLE CARE
2.0L L4 Engine
Automatic Coolant Service Fill
Instructions
The vehicle is equipped with a service
feature that assists with filling and
removing air from the cooling system
after service of components or when
coolant is added after being too low.
To use the service feature:
1. With a cold system, add coolant to
the indicated line on the
surge tank.
2. Replace the pressure cap on the
surge tank.
To activate the service feature:
1. Connect the vehicle to a battery
charger.
2. Turn the ignition on. See Ignition
Positions 0 223.
3. Turn off the air conditioning.
4. Set the parking brake.
5. At the same time, press the
accelerator and the brake pedal for
two seconds, then release.
6. At the end of the cycle, check the
coolant level in the surge tank and
add coolant if it is below the
indicated line. Turn the ignition
off, allow the Electronic Control
Module (ECM) to go to sleep, about
two minutes, and repeat Steps 2 6.
Listen for pump activation and
movement of the control valves while
watching the level of the coolant in
the surge tank. If the tank empties,
turn the ignition off, carefully remove
the pressure cap, refill to the indicated
line, replace the pressure cap, and
repeat Steps 2 6.
The fill and air removal process will
run for approximately 15 minutes.
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.
3.0L V6 Engine
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. 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.