I have a 2011 Ranger V-6 with 140000 miles, hearing some chattering comes and goes so I'm thinking it's time to change the belt and tensioner pulley as well. Tips tricks to make it go as smooth as possible. Thank you
Jim

 

Cold engine
Pull off the belt from the pullies
Spin each pulley manually to see if one is bad
It can be tensioner or idler or alternator or AC Clutch pulleys making a noise

If you can't tell which one, START THE ENGINE, yes with belt still off
You can run a cold engine without water pump or alternator for 1 to 2 min. but no longer
Listen
Engine bay will be VERY QUIET with no fan noise
If you now hear the noise its coming from the engine
4.0l SOHC engine need to have the timing chain tensioners changed every 100k miles, not hard to do but needs to be done ASAP if there is ANY noise

 

replaced the serpentine belt plus idle pulley and tensioner....easy peasy and all the chattering is gone. Nice and quiet. Now those timing chain tensioners....

 

I have the same engine in two vehicles. Rock Auto used to sell a Gates kit, which included the belt, idler and tensioner, for a lot less than buying all three individually.