Noisy Alternator?

[MTIbiza]

Tonight the missus came in from driving my car and complained about a horrid noise from the engine and the battery warning light flashing. I have been out and had a look but can't see anything obvious - and no warning lights. Started the car and everything seems fine, then the noise starts. It is coming from the alternator and it is really loud.

How can I test the alternator to make sure it is working ok? The belt seems to be in good condition with no fraying or cracks.

Any other suggestions as to what it could be or how to fix it?

I had a search of the forum but couldn't find anything that matched up.

Any help would be great!

Thanks

 

[RUM4MO]

Could be the alternator's shaft bearings that have failed, or the auxiliary belt tensioner's pulley bearing that has failed, or maybe the free-wheel pulley on the alternator (I don't know anything about that one as I'm a petrol head).

If you release the auxiliary belt and spin the alternator pulley and check the shaft end float and free side ways movement then you will probably work out if its the bearings.

 

[MTIbiza]

How do I go about releasing the belt?

 

[RUM4MO]

Find the belt tensioner and rotate it using a socket - if in doubt maybe get yourself a Haynes book for a Polo 9N - check that it covers this engine (roughly) first - Halfords should have them in stock - if desperate buy the Fabia one instead.

 

[bbewekim]

could always get some duck grease... apply it to each part of the alternator i.e. pully, tentioner etc. You'll know which one it is as the noise should stop.

 

[MTIbiza]

This morning I started the car up and the noise was horrid. it then suddenly stopped!

I have driven the car on and off all day and everything is fine! I'm going to keep an eye on it and see what happens. fingers crossed

 

[Guinness]

it sounds like the belt pulley. The pulley acts like the back wheel of a bicycle crank. Only turning in one direction or so im told. Which can cause the squeeling noice.

Another tip would be a wax crayon, sounds silly but we used to use it all the time to stop squeeling. A new pulley can be fitted easily without much hassel but requires a special socket to remove from the alternator.

Steps anyway to potentialy cure the squeel.

Buy new belt if needed and pulley.

Release belt tension.
Remove alternator
Remove pulley
Fit new pulley
Replace alt
Reset Tension