Yo tjg8675,
Try narrowing it down by using short length of garden hose or cheap mechanic's stethoscope aval. @ HARBOR FREIGHT for under $5.00.
BEWARE of fan, belts, pulleys, etc.
This is by Ford:
"Symptom Chart — Accessory Drive Belt Diagnosis
ACCESSORY DRIVE BELT DIAGNOSIS
Condition Possible Source Action
Excessive Noise/Belt Squeal
Seized accessory.
CHECK all accessories for free rotation and REPLACE accessory if necessary. REPLACE drive belt.
Loose drive belt.
CHECK condition and tension of drive belt. REPLACE drive belt or ADJUST tension of manually tensioned drive belt as necessary.
CHECK that automatic drive belt tensioner is within the indicator marks. CHECK for correct drive belt length if drive belt tensioner is out of operating range.
Rattle
Loose pulley or accessory.
CHECK for looseness and tighten.
Noisy Tensioner Pulley Bearing
Worn bearing.
REPLACE pulley per automatic belt tensioner pulley replacement procedure.
Belt Chirp
Misaligned power steering pump pulley.
ALIGN power steering pump pulley according to power steering pump pulley alignment procedure.
Severe Belt Flutter
Loose drive belt.
CHECK belt tension and ADJUST (manually tensioned belts only) if necessary. CHECK condition of drive belt and REPLACE if necessary.
Binding tensioner arm.
REMOVE drive belt from drive belt tensioner and VERIFY that tensioner arm is not frozen in position or that arm does not bind when manually moved throughout its operating range.
Frayed Drive Belt
Drive belt not seated correctly (poly-V belt).
REPLACE drive belt and VERIFY correct belt seating.
Severely misaligned pulley.
USE a straightedge to CHECK for severe angular misalignment between adjacent pulleys. CORRECT as necessary.
Tensioner pulley.
REPLACE tensioner.
Drive belt too tight.
REPLACE drive belt.
Drive belt worn out.
REPLACE drive belt.
Severely Glazed Drive Belt
Seized accessory.
CHECK all accessories for free rotation and REPLACE if necessary. REPLACE drive belt.
Loose drive belt.
REPLACE drive belt.
Improper Accessory Operation (Power Steering or Air Conditioning Does Not Work, Engine Overheats or Battery Does Not Charge)
Loose drive belt.
CHECK drive belt for looseness or GLAZING and REPLACE or ADJUST tension of manually tensioned belts if necessary."
Gates has neat stuff:
Serpentine Belt Wear Gauge
New and Improved Belt Wear Gauge - Easier to Use!
Belt Wear Gauge
The Gates Belt Wear Gauge was designed with input from automotive technicians. It is easy to use and gives instant pass / fail results. You can use it on or off the vehicle, one-handed, and even in places where you can't see.
How To Inspect Today's Belts
Belts manufactured before the year 2000 show obvious failure signs such as cracks. Today's serpentine belts wear out gradually, much like a tire, and don't always show signs of visual wear. A serpentine belt can appear to be in good condition when it's actually near failure. The New Gates Belt Wear Gauge provides a simple and reliable way to determine if a serpentine belt has lost enough material to negatively affect performance and warrant replacement.
To request a free gauge, click here.
- See more at:
http://www.gates.com/products/automotive/tools-and-sales-aids/belt-wear-diagnosis/belt-wear-gauge
Diagnosing Tensioner Failure @
http://www.gates.com/catalogs-and-resources/automotive-resources?&page=1&result=12&resourceCategory=Automotive+Aftermarket
On page 2,
Pulley Alignment & Tension
Tech Tip
Automotive
The source of belt noise is rarely from the belt itself. To ensure proper diagnosis, it is imperative to understand pulley alignment and tension.
- See more at:
http://www.gates.com/catalogs-and-resources/automotive-resources?page=2&result=12&resourceCategory=Automotive+Aftermarket#sthash.hAFe09bz.dpuf
Belt Tension Calculator
Calculator
Automotive
Quickly determine the proper tension for manually tensioned belts.
- See more at:
http://www.gates.com/catalogs-and-resources/automotive-resources?page=4&result=12&resourceCategory=Automotive+Aftermarket#sthash.3tsqpF6c.dpuf
