I was checking my oil level and noticed the coolant level was low. The existing coolant is a blue liquid but coolant is generally a yellow liquid. I have used water as a temporary substitute. Does the G37 require a special coolant that I am unaware of or can I use the yellow coolant?

 

OEM Nissan 50/50 coolant is blue. You will be fine adding water.

 

I hope you mean adding distilled water. Regular water does not get added to the coolant any more, only distilled. Typical tap contains minerals that will attack the aluminum parts of the cooling system causing premature wear.

How much did you have to add? I doubt adding a little will contaminate it much, but keep that in mind.

 

I run mine 75/25 water runs cooler than coolant but coolant protects the passage ways from rust and corrosion.