Hi Guys

 

Apologies, I know there are quite a few topics about alternators, but I couldn't completely clarify what my problem is so I thought I'd see if anyone could help!

 

So recently my aux belt started squealing pretty badly, and not long afterwards about a mile from home my battery light came on & there was a pretty bad smell of burning. Turns out the aux belt had disintegrated & part of it had melted onto the alternator pulley, hence the smell!

 

Using the above mentioned threads, I diagnosed a worn out tensioner as the source of the squealing, and a broken pulley as the cause (quite wobbly, so clearly bearings gone).

 

I replaced the tensioner & bought a new pulley, but I don't have the tool I need to swap them over, so I fitted the new belt anyway to see if I could just drive it a few miles or so to a garage that did have the tool to change it for me (assumed running it with a dodgy pulley wouldn't destroy the new tensioner if it was only for a short distance).

 

Anyway, when I started the car to test it, the battery light stayed on, and looking at the alternator I could see the fins inside weren't spinning at all, (despite the pulley moving freely) so the pulley was obviously worse than I thought!

 

What I am unsure of is whether or not the alternator is ok other than the pulley. From what I've read, the fins should move freely in one direction but lock in the other, but using a screwdriver, I could move the fins in BOTH directions. Is this right?!

Sounds like the pulley has come apart so the centre and outer are not really connected. Chance are it will disintegrate soon.

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Yeah, that sounds about right, as the centre splined part doesn't move, but the outer roller turns with the belt happily (apart from getting red hot!)

So I know the pulley is definitely goosed, but should I be able to turn the fins of the alternator in both directions with a screwdriver as I said? Hoping I can get away with just changing the pulley & not the whole thing!

Yes if it turns both ways the pulley is cream crackered.

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Is it only the pulley the determines how the fins spin then? IE with no pulley attached at all they can just spin in either direction freely, but with a working one they spin one way & lock the other?

I was worried that with them spinning both ways now it might mean that the alternator itself was broken, not just the pulley.

Yes its the pulley, the alternator will happily spin either way.

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Brilliant, thanks for your help, I appreciate it

At the risk becoming annoying, just one more thing - as the belt only drives the air con & the alternator, I assume it will be ok to drive a few miles without the belt on to get the pulley changed, the only risk being I might need to jump start the car afterwards?

The power steering pump is electric, so I would make sure the battery has plenty of charge before you start but you should be OK.  Also you will end up with fault codes galore stored.

Ah right, probably got lots of them anyway as I had to drive a mile or so home after the belt self destructed!

Thanks again.