I have a 96 integra rs, and I think I have a radiator leak. The fluid level is going down below the min line probably about once a week, and there is a little bit of fluid all along the top of the radiator. (Not directly on top, but a couple inches down where there is a slight overhang for it to settle.) It looks like there is more fluid on the left side, towards the cap.

So, my question is, why isn't my car overheating? (I live in the East Bay of SF area where it is hot).

Where should I look for leaks, and is it easier to buy and install a new radiator if I need one, or should I take it to a mechanic?