Have an intermittent grinding / dragging noise coming from the pulley (?timing) area that I'm trying to pin down. Both the alternator and tensioner were replaced prior to the noise starting. The ac compressor and the power steering pump are original. The fan clutch was replaced about 4 years ago and the water pump 8 years ago. Timing chain / guides / tensioner are all original.

I don't notice any of the common ps pump indicators (whine increase when steering) but noticed the fluid level was down slightly and that the pulley seems to have some inward - outward play with the belt off.
I also don't have any other engine symptoms like rough idle or any codes being triggered.

Any ideas on how to isolate the culprit?

 

The compressor only uses the clutch bearing when NOT engaged. Turn on the AC and engage the compressor. If the noise goes away, then that is the problem... Otherwise, you normally remove the belt and turn the pulleys one at a time and see if one feels "bad" or dragging. If the noise is only minor, then sometimes you can take a thin 1/2 inch pipe or conduit and place it on each pulley bearing and rest the other end on your ear. The pipe acts as a stethoscope and will magnify any noise. You can definitely tell the difference if you rest on a noisy bearing. ........ I would look at the IDLER pulleys and tensioner pulley as more common failure than pumps / fan / alternator.

 

Well ...

So I pulled the belt off and the tensioner spring was virtually solid, no other smoking gun on the pulley rotation, although the idler felt a bit tight.

Replaced the tensioner - same noise.

Per your and others advice I figured I'd look at the idler pulley ...
Found that the boss was actually snapped off even though the pulley felt solid.

My dilemma now is how do I fix this? Do I need to replace the timing cover?
Kind of bummed as not even certain this is the cause as the truck has 360K on it and the ps pump and ac are original as are timing chain and guides.