PLS HELP: What's this noise?

[e36Ballen]

View: https://youtu.be/CE-gN-Gde60

View: https://youtu.be/F_C0kQr6Z4Q


Just want to confirm. I'm about to buy a lower mileage alternator because I suspect it's where this noise is coming from. Alternator pulley used to not spin straight (due to a loose belt the previous owner didn't replace) which makes it a suspect (bad bearings). But with the new belt, it's spinning straight now after putting in 500 miles (it got straigthened) but I still hear the noisy ringing on idle. I tested it before when replacing the belt but I'm still not sure if it's the alternator, it seemed kinda solid and spins after I spin. Alternator charges well.

Already did the screwdriver and funnel test. Couldn't confirm still.

EDIT: It's noisy on idle, warm or cold, but pressing the gas makes it pitch and go away.

I already replaced:

1.) Tensioner Pulley & Assembly
2.) Idler Tensioner Pulley (by the alternator)
3.) A/C pulley tensioner
4.) New Belts (Both A/C & drive belt)

Pending to be installed:

1.) New Water pump

I'm suspecting a vacuum as well but I have no CEL. Car is solid and runs well. M44 1.9 engine.

If someone has an experience with this, would appreciate any input. Thanks

 

[t-tony]

My advice would be to remove the poly vee belt and spin each individual item by hand, Alt. W/pump, idler, tensioner etc. and listen for noise. It does sound like Alt. bearings but have alums ten with belt removed.

Tony.

 

[e36Ballen]

My advice would be to remove the poly vee belt and spin each individual item by hand, Alt. W/pump, idler, tensioner etc. and listen for noise. It does sound like Alt. bearings but have alums ten with belt removed.

Tony.

Yeah still feels like the alternator bearings. I'm worried that it could be the Timing Chain but I know Timing Chain is louder and doesn't do ringing. Thanks

 

[motco]

If it goes away when the revs are raised it could be simply a resonance of something. The audio on the clip doesn't really tell me anything but I'm a bit deaf. Systematically taking things off the drive as t-tony says isn't a bad idea either.

 

[Ianmc]

Mine does this, sprayed a little wd40 and it went away for a short time. My fix will be a replacement alternator, but it is original and charges well; one for the future.

 

[Mazza]

Ian, If everything else ok, then I’m sure it is possible to take an alternator apart and replace the bearings. The bearing numbers will be stamped on them and easy to obtain replacements.

 

[Ianmc]

Ian, If everything else ok, then I’m sure it is possible to take an alternator apart and replace the bearings. The bearing numbers will be stamped on them and easy to obtain replacements.

That's a good thought, thank you. Will look for a "how to" guide. Like to keep things as original as possible (except chrome stuff); only real limitation is that car is in daily use. Could be tricky if I get stuck!

 

[Grenville]

Could it be the belt in the pulley?

 

[Ianmc]

Not with mine, all belts/pulleys replaced recently (except alternator). Perhaps for the OP?

 

[e36Ballen]

Not with mine, all belts/pulleys replaced recently (except alternator). Perhaps for the OP?

Thanks for your input. I actually want to put WD-40 too lol.

Everything else is new except the water pump. I doubt tho that it's the water pump. I have a new water pump ready to be installed. So I think it's really the alternator. I just feel bad because the alternator is in good shape. It's just the bearings. I already ordered a lower mileage used alternator. Will post updates.

 

[e36Ballen]

Forgot to post an update. Yes, it is indeed the alternator. It's the alternator bearings being worn. Got a "new" reman alternator instead. Thanks fellas.