The short hose is a major PITA. you have to find a thin wrench (some crescent wrenches will work) to hold the adapter fitting in place while you use another wrench to get the line off.

It works best if you can wedge the handle of the wrench holding the fitting against something solid (not the radiator) and then you can use a breaker bar or some other form of leverage extender on the other wrench.

And if you put it on the low setting, an impact wrench is great for breaking the bolts loose. NOT taking them out and NOT putting them back in.