Coolant leak hint?

[Bradster]

UPDATE: I just noticed that the expansion tank did not empty after all. It is just below the minimum mark, but I know it was full. With the noise, I am moving on to the water pump, which, after reading the posts on replacing the coolant tank, it will be easier and cheaper to replace the pump! Anyone have a recommendation on the best reman water pump? At NAPA, Parts Bin, etc., they are all priced around $150 or so.

Thanks.