Annoying Engine Noise

[notamechanic]

I need some help. My 1990 Corollas has had an annoying engine noise for the last eight months. It sounds like it is coming from the A/C compressor. I have replaced the idler pully, and alternator. The A/C works terrific, and the noise persists. The noise sounds vaguely metallic and rythmic, not a belt squeal, and the car can be heard coming up the street. The water pump appears to be working properly with no leaks. I don't want to keep "throwing" parts at it without a better understanding on the source.

Anyone have any new ideas, as my mechanic friends agree the noise is under the hood.

AL

[martin_longbow]

Be very very careful with this

Get a very long screw driver/extension bar basically a long metal pole, even a jack handle and with the engine running place one end of the bar at the diferent engine components that you want to check, the noise should produce a vivration that you will hear clearer through the pole (cause you put the other end of the pole in your ear) this wil allow you to lsten to the noises and decide which is the sus part

it is the vibration you are picking up so put the pole firmly against the engine parts and against your ear, but watch the belts and any other loose dangling bits (better take off any thing that dangles from you, tie you hair up if you have it long) and do not burst an ear drum by ramming a pipe in it

It's something to do and I use this method a lot when looking for noises, works ok.

[Black Knight]

Very good advice (about the diagnostic technique and the safety precautions) :)

[Black Knight]

Very good advice (about the diagnostic technique and the safety precautions) :)

[Black Knight]

And don't you just hate it when it does that double posty thing. d'oh :)