RE: Belt tensioner, how to replace? 1999 3.8L
Replaced a belt tensioner on my GC last weekend. Don't mess with the alternator. Instead, get you a 'belt tensioner removal tool'. It is $20 or more depending on the quality. Or do like I did, and go to Advance Auto and borrow the tool for free.
With the tool, put pressure on the tensioner to remove the serpentine belt. Then you can work on the bolt that holds the tensioner to the motor.
Have seen alot written about OEM vs. Dayco vs. Goodyear, when it comes to the tensioner part. Save yourself some $$$, the OEM part had the Chrysler star emblem on the back, and "Dayco" on it too, so just buy it from Advance. Same part, lower price.
Then think about it, while you are in there, is it time to replace the belt too? How about the idler pulley?
Use the tool to put it all back together.