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 TankReporting Safety Defects to the United States Government
If you believe that your vehicle has a defect which could cause a crash or could
cause injury or death, you should immediately inform the National Highway Traffic
Safety Administration (NHTSA) in addition to notifying General Motors.
If NHTSA receives similar complaints, it may open an investig ...
GM Mobility Reimbursement Program
This program is available to qualified
applicants for cost reimbursement of eligible aftermarket adaptive equipment required
for the vehicle, such as hand controls or a wheelchair/ scooter lift for the vehicle.
For more information on the limited offer, visit www.gmmobility.com or call the
G ...
Engine Oil Life System
When to Change Engine Oil
This vehicle has a computer system that indicates when to change the engine oil
and filter. This is based on a combination of factors which include engine revolutions,
engine temperature, and miles driven.
Based on driving conditions, the mileage at which an oil chang ...