Engine is quot;tweeteringquot;

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Okay, I am NOT mechanically inclined, so please pardon my layman terminology!  
My '96 makes the strangest noise at times.  It is like a loud bird chirping and singing - like a belt that is too tight or too loose maybe?  It varies in its cyclical vibratto with speed - but only the speed of the vehicle, NOT the speed or RPMs of the engine.  It happens more regularly and is louder when the outside temps are cooler and before the engine warms up - but it can occasionally happen in the middle of a long drive even when it is warm outside.  Having the AC on or off has no effect.  
Any thoughts on this?  

Does it go away as soon as you touch the clutch pedal?

Classic symptoms of a noisy speedometer cable. Mine does the same thing when it is cold. If you want, you can go to the trouble of lubing it (seach Speedometer Cable for instructions) or live with it. I chose to live with it. For me, I drive it so infrequently when its cold, it wasn't worth the effort to remove the cable (that dude is not very easy to get out), so I live with it along with all the other squeaks and rattles.

for not being very mechanically inclined you did an excellent job of putting together the right important details.  well done!
+1 for speedometer cable.  Easy to figure out, because the noise comes from behind the speedometer gauge, while driving turn your head slowly to the right and left listening for direction to see if you can pinpoint the direction of the noise.  If it's from behind the speedometer you've got it.
you should lube it, otherwise it will fray and break.
OR alternative thought, a wheel bearing can makes such noises.  Often you can change the type of noise a wheel bearing makes when you turn the car.   Go around some left turns and see if the noise changes.  then try right turns.  speedometer cables don't care what direction you are turning.
Lastly Brake pad quot;Squeakersquot; make these kinds of noise intentionally to tell you that your brakes are wearing down.  But the noise only happens when you are NOT on the brakes.  if the noise stops as soon as you start applying brakes, then look to replace brake pads soon.
Richard

I must disagree with something stated above.....The speedometer cable is very easy to change.  Well...easy for me...maybe not for the quot;not mechanichally inclinedquot;.  I recently changed mine and it took all of 30 minutes (maybe).  That included time to put the car up on jack stands.


The speedometer cable is very easy to change. Well...easy for me...

You must have already known about that release tab that cannot be seen, under the outer cable at the speedometer. Congrats... a lot of people have actually pulled the instrument panel before finding that little !@#$%^amp;*()!!!!

It's been several months but I did pull the instrument cluster when I did the cable.  Takes about 5-10 minutes to get the cluster out.

Another idea......our friends car has a compression issue that hasnt been diagnosed or sorted out yet, but when you pull the PCV valve out while the car is running, the tweetering noise that his car is making stops.


Originally Posted by Captain Standish
Does it go away as soon as you touch the clutch pedal?

No....I should have mentioned that applying the clutch or fairly new brakes has no effect on this noise.  Soooooo...........it is sounding like a probable speedo cable.  I'll look into it a bit more tomorrow.  THANK YOU GUYS!  This is a very cool forum.

Indeed, when the chirping tweatering comes...it is coming from behind the instrument cluster area.  Yeah!  Good call you all.  Now...........
On another forum I frequented (Hummer Base Camp) people were always posting up repair help complete with step by step instructions and pics, etc.  Does anything like that exist to help this non-mechanically inclined guy try to replace (or lube or whatever) my speedometer cable???
*****EDIT*****  Never mind!  Haha  I used the Search as suggested and found great instructions - with pics!