I was experiencing squeaking noises from about a month ago and the noise was coming from the passenger side under the hood. Now it's time for replacing the pulleys. By the way, my taurus is 99 vulcan 3.0L with 150k miles on it.
Since I knew that idler and tensioner pulley bearings wear out easily from other TCCA postings, I decided to replace the idler and tensioner pulleys first.
step 1: choose the right tool
In order to replace the pulleys, you need to remove the serpentine belt first. Taurus has a tensioner pulley that automatically adjust itself to maintain proper level of tension and you need to rotate the tensioner bolt in order to loosen the tension manually. However, the problem is that you do not have enough room for its access and you need to exert strong torque to rotate the bolt.
Most auto part shops sell the tool named "serpentine belt removal tool." It is basically a long wrench bar and you can access the tensioner pulley bolt quite easily with it. The price is usually somewhere around $30. My local Advance Auto Parts shop had a rental program with $30 security deposit and you probably can find similar rental offers at your local part stores. I heard that Autozone has free rental program as well. Check gohim's posting at http://www.taurusclub.com/forum/index.php?...c=34528&hl=
You might go with similar, longer wrenches but this tool was very convenient and made the work quite easy for me.
step 2: loosen the tensioner tension
About.com carries a diagram for serpentine belt routing with pulley names. (You can also check Haynes manual chapter 1 for similar diagram) Check http://autorepair.about.com/library/images/bl403lib.htm
. P/S, C/S, W/P and ALT stand for power steering, crankshaft, water pump, and alternator. Among the two pulleys without names, the upper one is the idler and the lower one is the tensioner pulley. You don't need to consider air conditioner pulley for this work.
Now it's time for remove the serpentine belt. Using the serpentine belt tool, put the other end on the tensioner pulley bolt. (15mm) Haynes manual says that you need to rotate the tool _clockwise_ while you are standing on the passenger side. (My Taurus is 3.0L vulcan OHV
type.) When you try that, you are going to feel some tension from the tensioner spring and the tensioner pulley shifts a little to lessen the serpentine belt tension. While keep pushing the tool clockwise, take the serpentine belt off the pulleys.
step 3: check the noise & replace the pulleys
Try to rotate the pulleys by hand. If the bearings are failing, you can hear squeaking noise easily. The grease inside the bearing should exert damping force when you start to roll the pulley. If any pulley rotates freely without this damping sensation, you need to replace it too.
For my case, both idler and tensioner pulleys were making squeaking sounds when rotated. In order to take them out, you need to rotate the pulley bolt _counterclockwise_ this time. Again, you do not have sufficient room to put wrench in, so having the serpentine belt tool will help you quite much.
After that, put new pulleys in and tighten the bolts.
step 4: serpentine belt installation
Refer to the serpentine belt diagram and route the belt accordingly. While lessening the belt tension with the serpentine belt tool rotating clockwise as you have done before, put the belt back on. From my experience, putting the belt on the idler pulley as the last step was easier since the idler does not have any outside teeth for belt guide. Once the belt is correctly put on, the job is now complete!
total costs and others
It cost me about $80 for parts from NAPA. (idler and tensioner pulleys for $40, serpentine belt for $40) Probably you can save more at other discount stores. Now the squeaking noise is all gone. One nice thing I did not expect is that the car runs smoother. Idling got more stable and the acceleration feels smoother too.
Hope my experience can be helpful. Happy new year!