I have a ‘98 Ford Contour with 106K mi. Recently, I’ve been noticing a cyclic sound (kinda a subtle scraping sound only less metallic). The sound is so quiet as to be noticble only near idle w/ windows down, is roughly 3-4 Hz at idle, and is tied to engine RPM.
I popped the hood; the sound seems to be coming from the accessory side, and it does not seem to be in sync w/ the markings on the serpentine belt (though it’s somewhat hard to say.) The serpentine belt is at issue, because I replaced the alt. brushes and my first belt about 4k mi ago.
When I bought the car at 78K, I asked and was told the timing belt had been “serviced” at roughly 60K (which I took to mean replaced, but now I’m beginning to think inspected).
1. Am I on the right track here?
2. What do I inspect on the timing belt for condition–or just replace?
3. Ought I get just the belt, or the kit w/ pulleys, too?
4. Whattabowd’ the coolant pump?
Timing belts do not produce a certain noise when they are nearing the end of their life (or at anytime for that matter).
If there is any possibility your timing belt replacement interval has been exceeded,you need to replace the belt.
You should replace any idler pulleys or belt tensioners at the same time of belt replacement.
If it is necessary to remove the timing belt to replace the water pump it should also be replaced at belt replacement time.
Nows the time to do a coolant “drop and fill” good time for hose inspection and replacement
I don’t not understand the contex of the serpentine belt information.
TY for responding. The serpentine is at issue because the sound is coming from the side where both belts are–other than that, echo-location 
can’t narrow it any further. I thought if I could time the sound vis-a-vis the frequency of the little brand logo passing in front of my eye, it could determine which belt might be making noise.
The somewhat recent work on the serpentine belt is mentioned because I’ve found that one of the most likely times for a failure is just after working on a system. Though I imagine if I’d done something as FUBAR as mount the belt half-on a pulley, it’d’ve failed by now…
Maybe it’s the bearings from one of the pulleys that the serpentine belt rides on.
If you think it’s the serpentine belt, remove it, start the car, and see if the noise goes away. It could then be the belt, or any driven accessory. You won’t hurt it running it for a minute or less, cold. If the noise is still there, suspect the timing belt. They USUALLY don’t make any noise before they die, but I have seen a couple that did. According to the Gates timing belt replacemant guide http://www.gates.com/downloads/download_common.cfm?file=428-1466_web1.pdf&folder=brochure , the '98 requires inspection at 120K. I don’t know what they’d inspect. It is not an interference engine (I’m surprised.)