[AaronO]

Hello there -> having some funny chirping sounds coming from Alternator, hope you can help. [i30 FD 1.6CRDi / 160k mi]

Recently replaced the serpentine belt myself after having a near constant squeal noise. Old belt was quite cracked, not sure how long it was in there. Size was 1811mm. Replaced with 1810mm belt.

Now i'm experiencing another noise, which was perhaps always there but masked by the first noise. It's more of a 'chirp' and only occurs between 1,000 -> 1,500 RPM. I was easily able to identify the source by having a friend rev within that range, and putting my head close to the alternator.

Another symptom is that the belt appears to 'wobble' ever so slightly. I first thought perhaps it was slightly misaligned somewhere but after refitting it, it seems to be on correctly.

I took off the belt and spun the alternator pully by hand. While i can't spin at 1500 RPM (  ) I can notice an obvious warp in the pully as it spins, Like it's slightly bent. Video here -> Alternator warped - YouTube

I've never taken off an alternator but very willing to give it a go. Any advice what needs replacing ? (Just the pully or something else?)

PS. what would even cause the pully to warp?

Cheers! 
- Aaron

[asathorny]

are you sure that's not just the end float??? 

[sundiz]

Alternator had 2 bolts if I remember correctly. Quick and easy job. Expensive though... Have you changed the belt tensioner?

[AaronO]

are you sure that's not just the end float??? 

Not sure what's meant by 'end float'. Is this the piece that connects the pully to alternator? It seems like the pully itself is warped.

What parts would you suggest buying to fix? Pully and something else? Shall I just search ebay for 'i30 FD pully' or are there different variations?

Alternator had 2 bolts if I remember correctly. Quick and easy job. Expensive though... Have you changed the belt tensioner?

Which is the expensive part? the pully or something else?
The belt tensioner seems fine, it spins freely, there's no play on it, so i think the alternator is a good place to start.

[asathorny]

Fixing the Alternator | Toyota MR2 | Wheeler Dealers - YouTube

go to one minute and thirty nine seconds and watch carefully and learn.

You can thank me later, no I've changed my mind, you can think me now.

Always remember that GOOGLE is your friend 

[sundiz]

Alternator is the expensive part... at least here they cost 300-500€.

[BrendanP]

It may be the alternator pulley that is worn, there may be nothing wrong with the alternator itself. Most cars these days have a freewheel clutch built into the pulley, so when it wears it can start squealing and wobbling a bit. You'd probably have to get the alternator out to change the pulley.