Continuous engine rattle on passenger side; possible timing belt?

2.7L 6 cyl engine; I have had a rattle noise located around the belt/pulley area of the engine for about 4 months. Only occurred when the car was idling and it stopped at acceleration but last week after a long trip, the noise is now continuous. I did not change out the timing belt at 100k as my car has been running perfectly with regular scheduled maintainence. Now I'm concerned that maybe it's time and finances are not available. Also I'd like to mention that my a/c stopped working about a year ago (won't maintain coolant) and I read a notice that maybe the compressor may be the source of the noise also. Either way I think I have something major happening and I don't want to loose my engine. I have had diagostics run and no error codes are showing up. Any input would be greatly appreciated.