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 TankDifferent Size Tires and Wheels
If wheels or tires are installed that are a different size than the original
equipment wheels and tires, vehicle performance, including its braking, ride and
handling characteristics, stability, and resistance to rollover may be affected.
If the vehicle has electronic systems such as antilock ...
Navigation
OnStar navigation requires a specific OnStar subscription plan.
Press to receive directions or
have them sent to the vehicle navigation screen, if equipped.
Destinations can also be forwarded to the vehicle from MapQuest.com.
Turn-by-Turn Navigation
Press to connect to a live
Advisor.
...
Windshield Wiper/Washer
The windshield wiper/washer lever is on the right side of the steering column.
Move the lever to one of the following positions: HI: Use for fast wipes.
LO: Use for slow wipes.
INT: Move the lever up to INT for intermittent wipes, then turn the
INT band up for more frequent wipes
or d ...