New noise

[Italchic]

So out of the blue mine seems to have developed a new noise emminating from under the hood. Its a high-pitched whirring sound like a high-speed drill. Its matched to the engine rpm's and is most noticable upon acceleration. Anybody have any thoughts?

[azruss]

i had an alternator bearing go out that had that same sound. you need to do some sleuthing with a stethoscope so try to pin down the source. alternator, cam bearings, alt shaft bearing, dizzy bearing, timing belt bearing.

[Italchic]

Did as you suggested, I think it just might be the alt. So this means replacing the alt. How long do I have before I need to do this?

[majicwrench]

Don't think, verify. Remove belt and spin alt and anything else. See what has bad bearing. No point putting it off, sooner the better.
It could also be something to do with T belt, tensioner pulley etc. So find out for sure what it is NOW.

[Italchic]

I'm no mechanic, if I remove the belt am I supposed to spin the alt. by hand? and if so what am I listening for? How will I know if its the alt. bearings?

[Weelan]

And they say you don't learn from tv...

http://www.youtube.com/watch?feature=pl ... Ms#t=1445s

You can spin it without removing it. just get the belt off the alternator and spin the belt guide thing.

[majicwrench]

Yup, spin by hand. Should be almost silent. If brg bad it will sound like it does with engine running. Wrrrrrrrrr. Spin water pump too.

[azruss]

spinninng it by hand will not give you the same sound, but you can feel how smooth it spins. Even if the bearings are bad, you can take the alternator to an alternator shop. should be much cleaper than buying a new alternator.

[Italchic]

Well I haven't taken anything apart yet but I did listen to the alt. the way the old timers did, I put a wooden rod against the alt. case and did hear a whirring sound, but then again I don't know if thats just normal with the spinning of the rotor.

[donm]

Best way to eliminate alternator as noise source is to remove the belt altogether and run the engine.

[RRoller123]

Good idea. Just be careful not to run it very long as the belt also runs the water pump.

[bobplyler]

Just be careful not to run it very long as the belt also runs the water pump.

So if the noise goes away, it would indicate either the water pump or alternator.

[azruss]

water pump bearing doesnt normally whine, you would also notice play in the bearing (pulley would move when the motor was on).

[bobplyler]

When I replaced a water pump, it was rattling. Of course you could only hear it when it was off the car, and shaken.

[Italchic]

Thanks to all for the advice. How long do I have before I should do this milage-wise? The reason I ask is because the its going to be in the 90s with high humidity and there is no way I can work on it under those conditions. Can I drive it for short distances?