Intermittent whining noise from engine bay

[Fudman]

I did a search for whining and whine but could not find any symptoms that mirror my situation. I get a periodic whining noise from my engine bay. It starts softly and gradually builds up volume as engine revs increase. It appears to be directly related to engine rpm, as it begins at around 2,200-2,500 rpm as a soft whine and then builds volume. If you lift off the throttle, it will immediately cease. It happens most often when it is really cold (<20F) but will also happen when warmer (<35F). It's been happening for a few years but the intermittent nature of the problem means I always forget to try and troubleshoot it (this is my wife's SUV).

I thought it was a tachometer cable that needed lubrication but I cannot determine if our truck has a tach cable. My Haynes manual has nothing on the instrumentation and this forum doesn;t mention anything either. It is not my front bearings, as both have been replaced within the last 5K. It is not likely the PS pump as it occurs when we are going straight, without turning. I thought it might be the belt system, based on some comments from this forum.

Any suggestions on what might be the cause of this noise would be greatly appreciated.

 

[drew76924]

possibly comming from the Torque converter or tranny pump area?

 

[HiImBrian]

Loose pulley or A/C compressor clutch can cause a hum or whine. Take off (better to replace) your belt and feel all your pulleys for any play. If it happens when revving in park it won't be trans or TC related.

 

[extra-medium]

I have some whine when my a/c compressor is on. I was thinking I am looking at replacing it come spring time.

 

[HiImBrian]

I have some whine when my a/c compressor is on. I was thinking I am looking at replacing it come spring time.

It may not be your compressor and just your clutch. Have a reputable A/C guy look at it. You may not have to pay up for a whole new compressor.

 

[D Hook]

Don't believe there's a mechanical tach cable. Should be all electrical.

 

[HiImBrian]

Don't believe there's a mechanical tach cable. Should be all electrical.

They switched to throttle drive by wire in late 03, but that's it as far as I know.

 

[D Hook]

I think he was talking about a tach cable, not a throttle cable.