Heres the lowdown:Out of the blue,I notice white smoke billowing from underhood.I take a look and see green coolant pooled along the top of the radiator/left edge of the hood.No codes or strange behavior otherwise.This only happens when the car moves,no leakage when parked.Any help would be greatly appreciated,not exactly comfortable seeing ANY smoke underhood. PS:Water pump replaced at 160k.

 

If you can't see the crack or leak, have the system pressure tested. If it passes that test but still pours coolant out when driven then chances are you have a blown head gasket.

 

or it's just the rad that needs to be replaced

 

I would think there would more to see and feel if the headgasket were bad. Get it tested, but I think you need a new radiator. Get one from the group deal. Very easy to replace. I just did mine three weeks or so ago. I had the same symptoms as you. I have some pictures of mine here:
http://target.new.photos.yahoo.com/s...60762373221081

 

It's common for the plastic at the top of the radiator to crack after 10 years of heat and abuse. Check around the top of the radiator. And if it is cracked don't bother trying to patch it. That does not work (for long at least)

 

Just going to say the exact same thing... I patched mine every week with JB Weld for 2 months :P Then I broke down and bought a new one.