water pump

It's essentially the same as changing the timing belt, which you might as well do while you're at it. You'll find illustrated instructions in the miata.net Garage section:

The timing belt job does not require a professional mechanic but don't be fooled it is not for an inexperienced mechanic either unless he's got good basic skills and can follow direction very carefully. Minor mistake here (one tooth off) and you can have a car that runs like s*it and you've got to start over! (don't ask me how I know that).

Chris

Actually, it's easy to get one tooth off-- unless you can block the cams from rotating. The new belt is a bit shorter than a used one. The tensioner complicates matters.

Dean,

It is certainly a strange co-incidence that the water pump problem was initiated because you changed the radiator. Did you change a hose that might be leaking coolant in such a manner as to suggest a water pump failure?

Of course, the pump may have been leaking all along and you didn't focus your attention on it until you had to work on the radiator.

I don't know about the '97, but in the '90 (where I have changed the timing belt and water pump a few times) the removal of the radiator, while making things a little better, isn't all that necessary to work on the water pump.

Ken