The video clip above shows a great tutorial on Coolant Replacement for an Infiniti G35. Follow the instructions and you’ll have a great set up for your Infiniti.
Below are some replacement parts that you can consider changing out once you’re replacing the coolant:

• ACDelco 12R6 Professional 13 P.S.I. Radiator Cap
• Gates 22967 Radiator Coolant Hose
• Infiniti Nissan G35 Silicone Hose Kit Red
• HPS (57-1048-BLUE) Silicone Radiator Hose Kit for Infiniti G35
• Infiniti Genuine Engine Cooling Radiator Reservoir Tank Assy 21710-AL500 G35

A good replacement antifreeze would be; Prestone Extended Life Antifreeze (50/50) features a blend of 50 percent antifreeze/coolant for temperature and corrosion protection and 50 percent demineralized water for heat transfer protection, and is compatible with any antifreeze/coolant, regardless of color.

For use in all makes and models of cars and light duty trucks, this patented formula provides a high degree of performance durability and carefully balanced protection against temperature extremes and rust corrosion of all cooling system metals, including aluminum. Good for 5 years or 150,000 miles, this antifreeze meets or exceeds ASTM D3306 and D4985 for corrosion protection.