Weird alternator noise after pump replacement - Video added

Post by **sjmtlewy** » 21 Mar 2010, 20:09

Just replaced the water pump in my 1.9DG. Everything seems to be running well, but there's now a whirring/whistling noise coming from the alternator area. I'm fairly sure it wasnt there before. Didnt really touch the alternator - just hit it with a rubber mallet a couple of times to get it moving in order to fit the belt. Any ideas? I also had the dizzy cap off, might that be the source of the noise somehow? Also fitted new v-belt, but I dont see why if that were noisy it would just be coming from one spot.

Post by **Ian Hulley** » 21 Mar 2010, 20:12

Sounds like you've overtightened the alt. belt and fooked the alt. bearings.

Ian.

Post by **kevtherev** » 21 Mar 2010, 20:45

loosen the belt.. have about 1 inch of movement on the longest run

Post by **sjmtlewy** » 21 Mar 2010, 20:57

Okay, i'll see if loosening the belt makes any difference tomorrow. Just in case - how much should an alt refurb cost?

Post by **VWCamperfan** » 21 Mar 2010, 23:27

Oddly a new belt will do this. Replaced mine a year or so ago and it did exactly the same thing! Tensioned correctly too although this is important as mentioned above and not to be missed!
I think its got something to do with the belt design. The belt I fitted has notches cut out on the inside edge but the belt I had before that was just a normal V-belt with a constant inner edge.
I actually quite like the sound it makes now. Really should get out more!

Post by **sjmtlewy** » 22 Mar 2010, 07:57

VWCamperfan wrote:Oddly a new belt will do this. Replaced mine a year or so ago and it did exactly the same thing! Tensioned correctly too although this is important as mentioned above and not to be missed!
I think its got something to do with the belt design. The belt I fitted has notches cut out on the inside edge but the belt I had before that was just a normal V-belt with a constant inner edge.
I actually quite like the sound it makes now. Really should get out more!

Thats interesting, because this belt is a slightly different design (yes - I need to get out more too

). I'll add "see what noise the old one makes" to my test list. Cheers.

Post by **Ian Hulley** » 22 Mar 2010, 08:44

VWCamperfan wrote: The belt I fitted has notches cut out on the inside edge

These were designed to go round smaller diameter automotive pulleys the notches making for less strain on the outside surface than the standard wedge bely which was designed for industry primarily.

Post by **kevtherev** » 22 Mar 2010, 13:29

sjmtlewy wrote:Okay, i'll see if loosening the belt makes any difference tomorrow. Just in case - how much should an alt refurb cost?

If as Ian suggests you have shagged the bearing then just buy a new bearing and fit it

1 bearing versus £80 replacement

no brainer

Post by **sjmtlewy** » 26 Mar 2010, 10:39

Had the alternator serviced. They replaced bearings, rotor and regulator.

Still making the same noise. I've tried loosening and tightening the belt, but it doesnt make any difference. Video of it here (very dark, but you can hear the noise as I rev the engine) : http://www.youtube.com/watch?v=Tu7fuATIskA" onclick="window.open(this.href);return false;

Any one able to hazard a guess?

Post by **sjmtlewy** » 28 Mar 2010, 16:16

Points go to VWCamperfan - Put the old belt back on, tensioned it nicely and the noise was gone! So turns out JK sell very loud belts...

Cheers for the help.

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Weird alternator noise after pump replacement - Video added

Weird alternator noise after pump replacement - Video added

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Re: Weird alternator noise after pump replacement - Video added

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