ticking noise at the front of the engine
 

Hi, I have an 88 300ce with 170,000 miles on it. I've noticed there is a ticking engine noise (da da da da) from the front of the engine. It seems like a pulley problem. It is difficult to narrow down to which pulley is the cause of the problem. Beside the ticking noise, the cars drives pretty smoothly without any noticeable permance problem. So here are my questions:

1) Does this sound like a pulley issue or something else?

2) If it is a pulley issue, any easy thing that I should do first like tightening the bolts, etc before attempting to replace a pulley?

3) Any tip on diagnosing which pulley is the cause?

4) which pulley is more likely to fail?

5) Is it difficult to change pulley? (I do my engine and transmission oil change, brake pad and fluid change, coolant change, and other minor repairs)

6) Any special tool needed that a weekend mechanics might not have in his garage?

Thanks very much
Wawago.