The vehicle must be on a level surface when checking the coolant level.
It is normal to see coolant moving in the upper coolant hose return line when the engine is running.
Check to see if coolant is visible in the coolant surge tank. If the coolant inside the coolant surge tank is boiling, do not do anything else until it cools down.

If coolant is visible but the coolant level is not at or above the mark pointed to, add a 50/50 mixture of clean drinkable water and DEX-COOL coolant.
Be sure the cooling system is cool before this is done.
What to Use
How to Add Coolant to the Coolant Surge TankRemote Keyless Entry (RKE) System
For vehicles with the RKE transmitter, it may work up to 60m (195 ft) away from
the vehicle.
Press the key release button to extend the key blade. The key can be used for
the ignition and all locks.
Press to unlock the driver door
or all doors and the liftgate.
Press to lock all doors ...
Service Vehicle Soon Light
For vehicles with this light, it
comes on if a condition exists that may require the vehicle to be taken in for service.
If the light comes on, take the vehicle to your dealer for service as soon as
possible.
Owner Manual Indicator
This symbol is shown when you need
to see the owner manual ...
OnStar Additional Information
Transferring Service
Press to request account transfer
eligibility information. The Advisor can assist in canceling or removing account
information.
Selling/Transferring the Vehicle
Call 1-888-4-ONSTAR immediately to terminate your OnStar services if the vehicle
is disposed of, sold, trans ...