Try a new clamp... try cutting back the hose a bit for a fresh end... might have a crack where the hose nipple solders in and when you lift the blade and tweak the frame it leaks. You don't have the blade on in the summer... do ya?

This needs to be attended to cause it is an engine overheat waiting to happen. The cooling system must have integrity as it is under pressure when hot.

The cooling system and hydraulic system are separate and never the twain shall meet.

That's right, no blade in the summer. Not yet anyway, I just got the blade, but I'm already scoping the yard for applications.

I'll give the clamp a shot, thanks. When you say, 'lift the blade and tweak the frame,' does that mean it might be pressing on or pinching a hose or something? Or just that the whole thing(frame) jostles when the blade is lifted?

No, you have a hydraulic lift cylinder and there will always be some ancillary axial torque generated. There is nothing wrong with your lift system.

There is a leak in your cooling system. Might just be the end of the hose deteriorated where the clamp is. If you have room cut the hose back as little as you can to get a fresh end and re-clamp... snug, don't crush the hose and check for the leak.

If you can't find the leak get the tractor to someone who can before you win yourself an expensive repair.