My '98 Protege makes a high pitched whine for the first couple hundred yards when both the engine and outside temperature are cold (below freezing). It doesn't sound like a squealing belt. The sounds is an annoyingly high pitched metallic whine that increases in frequency (and volume) as the engine revs. I think it's one of pulleys (or bearings) on one of the accessories, water pump, or the A/C compressor, but I can't figure out which one when looking under the hood. I suppose it could also be one of the belt tensioners or idler pulleys. So, the question is this: how can I figure out which one is the culprit?

2 Answers 2


Rubber tubing is a cheap alternative to a stethoscope. You can buy a couple feet of it for a couple dollars at any hardware store, just be careful where you point it.

Thank Click & Clack for that, it worked for me.

  • +1 This should work almost as well as a automotive stethoscope, except it won't block ambient noise quite as well.
    – S_Niles
    Mar 15, 2011 at 6:13

Use an auto repair stethoscope or even a long socket extension as a substitute to listen to each pulley when you start the car.

If it's truly a bearing issue, you'll hear it right away when you find the affected part.

  • 1
    Re: the socket extension trick: I take it you mean aiming the extension at the suspected part and holding your ear up to one end? Might be worth clarifying. Mar 14, 2011 at 16:02
  • 2
    Yes, but you want to make contact with a stationary area of the pulley (usually the fastening bolt) to listen to the bearing noise.
    – kkeilman
    Mar 14, 2011 at 18:19
  • like this
    – elrobis
    Dec 7, 2016 at 17:44

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