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 TankCustomer Assistance Offices
Chevrolet encourages customers to call the toll-free number for assistance. However,
if a customer wishes to write or e-mail Chevrolet, the letter should be addressed
to:
United States and Puerto Rico
Chevrolet Motor Division
Chevrolet Customer Assistance
Center
P.O. Box 33170
Detroit, MI ...
Information Displays
Driver Information Center (DIC)
The DIC displays information about the vehicle. It also displays warning messages
if a system problem is detected. See Vehicle Messages on page 5-26. All messages
appear in the DIC display in the instrument cluster.
DIC Operation and Displays
The DIC has differ ...
Winter Tires
This vehicle was not originally equipped with winter tires. Winter tires are
designed for increased traction on snow and ice-covered roads. Consider installing
winter tires on the vehicle if frequent driving on ice or snow covered roads is
expected. See your dealer for details regarding winter ...