radiator holds water, was leaking out of the bottom when everything was hooked up.but didn't seem like it was leaking as much as i put in. hoses seem fine. is the t- stat in top of the radiator? S5

 

it should be underneath the top hose housing on the block

 

Not really understanding. You say the radiator is holding water, but then it's leaking at the bottom? Do you mean the connections are leaking?

How old are the hoses? Are you reusing the stock spring clamps? Spend the money and get new hoses and better screw clamps (10x easier to work with anyway).

FYI the T'stat is located on the water pump outlet feeding the top radiator hose. If the t'stat is used and/or you don't know the mileage on it, just get a new Mazda one.