Ok, there are 3 possibilities.
1 - Idler or Tensioner Pulley Bearing going bad
2 - Weak tensioner
3 - A/C Clutch Bearing going bad
To check for bad Idler or Tensioner Pulley bearing going bad, with can of spray lube in hand find the 2 pulleys(DO NOT START VEHICLE YET) spray 1 of the pulleys at the center bolt. Start engine, if noise is gone for a couple minutes then returns replace pulley, If noise still present turn off vehicle and spray the other pulley and start engine, again if noise is gone for couple minutes and returns replace pulley.
If noise is still present turn off engine, spray around the A/C Clutch and pulley area as best you can, start engine, if noise is gone for couple mminutes then you will have to change the clutch assembly if available if not then will need to replace A/C Compressor.
Tensioner - while engine is running watch the tensioner does it appear to move excessively? If so replace tensioner assembly.
Friday, December 3rd, 2010 AT 7:10 PM