Timing Chain Replacement

Okay so I opened it up to check if anything was grinding or to see if there was any metal flakes anywhere but nothing, I had someone rotate the crankshaft while I checked for any scraping or brushing and nothing. To give you a better idea of where the sound is coming from I am attaching a picture. This is where the pulley goes on to drive the water pump. It seems everytime I rev the engine it squeals but its not the belt

And also to when I put my car in gear it dies what could that be

Yes engine runs smooth during idling just only when I put it in gear does it run rough or die

Hello. I am looking at buying a 2002 Ford Escape xls with 135K miles on it. I am trying to find out if the car has a timing chain or a timing belt and if there is a difference between the two other than material. Do they both perform the same function? If it has a chain, how important is it to know if it's been changed or not? Do they generally need to be changed? Do you know if 4500 is a good price? Also, if there are any issues with this particular model that I should be aware of I would appreciate it very much if you will tell me about them. Thank you! I am so broke that I can't afford to donate much, but will give 10 dollars. Thanks, again.

Thank you both. I should have mentioned that it is a V6. Roy, at what point does an engine overhaul need to be done and do you have an idea of the cost? Thank you so much.