I just refilled the freon in my Civic and in my GF's Silverado using one can each. Of course the Civic is a 1999 and the Silverado is a 2000. It made a big difference, but I think they could have taken two cans each.

I'm assuming the Z uses just one can since it isn't that old? Is it too early to put freon in it? It's very hot here in Houston.

 

Normally unless there is a leak you don't have to top off freon. The A/C is a sealed system. At least that is what I have always heard.

 

Yeah you shouldn't need to be refilling any car unless there is a leak.