I was wondering the same thing since I will be doing a flush in the next week or so. The FSM says to use Genuine Nissan Long Life Antifreeze, but its pretty expensive. I would think any antifreeze made for aluminum engines(green) would be fine. I remember there was a controversy about this in the 350z forum, that the prestone coolant made for aluminum blocks still wasn't recommend for Nissan engines. IDK...
*I just read this on Popular Mechanics about choosing the right coolant.
"The green in most Japanese cars contains no silicates, so it's not the same as the green in the parts store"
http://www.popularmechanics.com/cars...oducts/1272436