Since it's a new radiator, check for molding burrs on the bottom of the stub where the hose to the reservoir attaches. The Chinese knockoffs currently on the market seem to have a problem with that.

 

Mk, you just lost me. WTF? There isn't any coolant leaking out at the top of the rad where the reservoir hose goes. Wouldn't that be the case if there was an air leak there? Although, given the fact that I have now dedicated my Friday night to working on the beast, I'll check that too. On tonight's agenda--change fuel filter (trusty can of Liquid Wrench at hand), flush cooling system, and add Lucas fuel system cleaner--oh, and change rad cap. And check the damn hoses for leaks again. Good thing I'm married or I would REALLY be ranting about losing a Friday night.

 

A leak in the hose system will prevent coolant from returning to the radiator as the engine cools off. It may not necessarily leak much coolant out.