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 TankHead Restraints
Warning
With head restraints that are not installed and adjusted properly,
there is a greater chance that occupants will suffer a neck/ spinal injury in a
crash. Do not drive until the head restraints for all occupants are installed and
adjusted properly.
Adjust the head restraint so tha ...
Accessories and Modifications
Adding non-dealer accessories or making modifications to the vehicle can affect
vehicle performance and safety, including such things as airbags, braking, stability,
ride and handling, emissions systems, aerodynamics, durability, and electronic systems
like antilock brakes, traction control, a ...
Engine Overheating
The vehicle has an indicator to warn of the engine overheating. See Engine Coolant
Temperature Warning Light on page 5-18.
If the decision is made not to lift the hood when this warning appears, get service
help right away. See Roadside Assistance Program on page 13-5.
If the decision is made ...