Ive got a slow drip leakat the upper radiator hose clamp, engine side.
My ? is will I lose much coolant if I replace the hose and T stat?
And will I need sealant for the T stat gasket? Should I drain some coolant first?

 

You'll have to drain the coolant below the level of the hose first, theres a stopcock on the bottom of the radiator, its white. If the fluid appears to be okay and nice and green, you can put it back in the radiator, if not, replace it.

Shouldnt need to put anything on the gasket either... also, use a Honda t-stat, theyre much more reliable and accurate than the parts stores ones.

 

The T'stat is not in the engine side fitting on the upper radiator hose. It's on the lower radiator hose, engine side fitting. Usually air intake is removed to access.

good luck