Strange noise

[SanAnEliseMan]

While reving the car in neutral today I noticed that when the rpms get around 5k the engine makes sort of a ringing sound almost like an old fashioned door bell. . . has this happened to anyone else and does anyone know what may cause this? Car seems to be running better than ever after another weekend of TLC, but worried about the noise. . . please advise oh wise ones.

[So Cal Mark]

does an old fashioned door bell, go "ding dong" or " bzzzz"?

[SanAnEliseMan]

bzzzzzzzzzzzzzzzzzzzzzzzzzzz

[So Cal Mark]

maybe the timing cover or exhaust heat shield vibrating

[JeremyB]

I've currently got 2 of the noises you described. I am convinced teh oldest noise is a heat shield. It starts buzzing/vibrating at around 4k rpm. It quickly stops the noise around 4500 rpm.
The other one has to involve the alternator. I recently replaced it with a rebuilt with internal VR. Around 3k rpm, I got a high pitch vibration. It almost sounds like the fan blades ot the alternator are vibrating. I initially thought the belt might be a little loose (So, like a dumbass, I went to tighten an alt bolt with a hot engine, and burned the hell out of my hand when it hit the exhaust manifold... Lesson learned). I then read that a very similar noise was described on another car. It turns out the noise was related to the bolt ont eh alt mount bracket was not tightened enough.
If you can narrow it down to a certain rpm range, have someone get it to that rev point, and try to isolate the noise.

[SanAnEliseMan]

Thanks I will check tonight. . . I think it could be any of the 3 mentioned above since I took apart that entire area this weekend. I will let you know.