[Craig00071]

Had what I thought was a faulty/worn out idler pulley assembley.
The pully was shaking and noisy but it was the alternator clutch bearing which was causing drag on the serpent belt and giving the idler pully a hard time.

A new OEM alternator was $500+.
Hyundai wants $1500.
Got one off a wreck for $140.

Problem solved.

[Mike SX]

That's the way to do it 

[asathorny]

Excellent, well done 

[eye30]

Result.

I take it it is out of warranty.....

[beerman]

How many K's?

[Phil №❶]

Don't know what an alternator clutch bearing is, but anyway, these bearings are commonly wearing out on my old GMH vehicle. I just take the alternator and exchange it for a recon one at the auto electrician, then I know the regulator, diodes, brushes and bearings are all replaced.

[Craig00071]

I have over 272000km now. Oh yeah, today it was 272222.
Apparently the alternator cuts in and out as required. The clutch system helps so the alternator isn't constantly sapping engine power.

[beerman]

272,000 is a good innings.....

[Asterix]

VW have had that kind of clutch in the altenator bearing for the last 10 years,, and when faulty, same issues.

[Phil №❶]

CORRECTION

Apologies to Craig00071 for giving mis-information. 

The i30 IS fitted with a clutch pulley. Here is some info and for me, learned something new today.

http://www.decouplerpulley.com/files/Alternator%20pulley%20technologies.pdf