Screeeeeeeeeeeeeetching Alternator

[Mr Cerbera]

As some of you will know (having been bored my my dozens of questions) I replaced my shreaded Alternator Belt.

I have just started to be able to start her regularly now, as I replace more equipment
BUT
I have the most ear-splitting screeching from what feels like the Alternator.
I can't believe that the belt is not sufficiently tight so I wondered if any of you Guys recognise the cacophony.
Could the bearing in the Alternator be destroyed ?

As usual, any and all comments will be appreciated

[TwinKam]

It does sound 'belty', Paul. Belts often need retensioning after the initial run period ...not so much stretch as bedding into the grooves.
Try it and see if it makes any difference at all.

[gruffalo]

I had something very similar once. It was the bearing in the air conditioning belt tensioner.

That sounds squeaky rather than screeching to me.

[Mr Cerbera]

TwinKam said:

It does sound 'belty', Paul. Belts often need retensioning after the initial run period ...not so much stretch as bedding into the grooves.
Try it and see if it makes any difference at all.

Cheers Rik,

I would have had a crack at that, if it weren't such a massive PITA to reset the pair of nuts and bolts which retain the Alternator, with the Injection System getting in the way.
I was just needing some supportive advice before I start the nightmare that I will invariable create

Ooh, that reminds me, someone suggested putting WD40 on the ADB to help it settle in.
Does this sound mad to you ?

gruffalo said:

I had something very similar once. It was the bearing in the air conditioning belt tensioner.

That sounds squeaky rather than screeching to me.

Cheers Martin,

Good alternative suggestion but I haven't altered anything to do with the tensioner and, when I get my head closer to the sound, it really does feel that it's coming from the Alternator.

"That sounds squeaky rather than screeching to me." Yeah, squeaky as in a flock of mice being impaled upon red-hot pokers

Ooh, talking of which. I have never been confortable with A/C. Perhaps I could remove it in an attempt to test if it is the problem ?
Tensioner off? Belt off ? A/C Pump off ??
I guess that there's a plethora of pipes which contain unpleasant liquids as well.

Any foreseeable probs if I just remove the Tensioner and Belt ??

Your thoughts ?

Ta !

PJ

[spitfire4v8]

If the belt is indeed tight then ... Charge your battery .. or sort any poor battery / starter / earth connections ..

starting is very laboured, and if the battery is low the alternator will be trying to dump a lot of power into the battery which in turn requires a lot of power to be transferred through the alternator drive belt, which only has a small wrap-around of belt because of the tiny alternator pulley size.

[Skyrocket21]

Totally unlrelated, but we have a honda that makes the screeching noise when hitting a puddle.

So my suggestion would be, the belt maybe contaminated with something, wd-40 etc, it might be worth trying to clean the belt (engine off obviously) with some ipa etc. It might stop the screeching or slipping noise.

[Penelope Stopit]

Are you able to get a finger in there and touch the pulley (no don't be silly, not with the engine running), it will be very hot after a minute or two if the belt is slipping

Quick test - Engine running, turn high beam lights, blower and anything else you can think of on, you will hear the belt screeching more with those electrical loads on if it is the belt causing the noise

A bad drive end alternator bearing will give a whine rather than a screech

Edited by Penelope Stopit on Thursday 5th November 10:16

[TwinKam]

Simply remove the AC belt if you want to eliminate the compressor and the tensioner from the equation.
I'm not familiar with the 4.5 set-up (mine is a 4.2), but is it not possible to prod the belt in the middle of its run with a screwdriver or somesuch? OBVIOUSLY, ENGINE STATIC!
And don't put WD40 on anything (except a raging fire), dreadful shte it is.

[frontfloater]

" Totally unrelated, but we have a honda that makes the screeching noise when hitting a puddle. "

My S2 began doing this after a service - whenever I went over a pothole or bump it would make a horrendously loud screech which prompted pedestrians far down the road to turn round. It turned out that the mechanic had used a belt which was too long, and raised the alternator to take up the slack. It was then so close to the underside of the bonnet that slight bumps caused the spinning alternator to come into contact with the GRP.

BOB

[Mr Cerbera]

Hi Guys,

Well, I can't believe it.

When I fitted the new Alternator Belt I was worried that I may have overtightened it.

Thankfully, due to your comments and advice, I removed the A/C Compressor to get a better look
and I found a belt looser than Twiggy's.
Many thanks, once again, for your combined comments and help

A real slapper....

[FarmyardPants]

Hi Paul
Something looks fishy about that pic - the alternator pulley looks to be touching the nut at the top but not the bottom, unless it’s an illusion?

Edit: also the belt looks a bit shagged

[lancepar]

I agree with FP, when the pic is enlarged it does look like the pulley may be loose on the alternator, but there are no witness marks to support this on the inside of the pulley, might be worth checking though.

[Penelope Stopit]

I reckon it's down to camera angle

Have never managed to strip an alternator nut and turn it up tight to the pulley

Nut looks straight on to the rotor shaft at the top 180 degrees

[FarmyardPants]

Penelope Stopit said:

I reckon it's down to camera angle

Have never managed to strip an alternator nut and turn it up tight to the pulley

Nut looks straight on to the rotor shaft at the top 180 degrees

I don’t mean the centre shaft with the nut on, I mean the ring of metal in contact with the belt.

[WIL35]

I think it is the depth of the pulley that is making it look off centre. Can see it in the photo below with it removed:

[Penelope Stopit]

FarmyardPants said:

I don’t mean the centre shaft with the nut on, I mean the ring of metal in contact with the belt.

Ok then, wasn't even close was I

As above, it's a real deep pulley

That said you may well have spotted something but.........

[lancepar]

Penelope Stopit said:

I reckon it's down to camera angle

Have never managed to strip an alternator nut and turn it up tight to the pulley

Nut looks straight on to the rotor shaft at the top 180 degrees

Here is a new pulley and a enlarged image of the one from MrC's pic.









Edit:
Too late as usual

Edited by lancepar on Tuesday 17th November 15:15

[Penelope Stopit]

Are all the locking washers offset like this or this another illusion?

Edited by Penelope Stopit on Tuesday 17th November 15:23

[Penelope Stopit]

lancepar said:

Too late as usual

Never too late to a party

[FarmyardPants]

Yes I think I was suffering from parallax illusion confusion. Needs tensioning. As you were.