Please listen to my Bongo - it's twittering at me

Technical questions and answers about the Mazda Bongo

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ICBongo
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Please listen to my Bongo - it's twittering at me

Post by ICBongo » Wed Sep 17, 2014 5:39 pm

Hi,

Over the last couple of journey I have noticed a noise that's got a little worse every time. It's an intermittent twittering noise. I've done a recording of it from the passenger side as this seems to be the loudest place. The seats were up and it was idling on the drive.

In the recording I have it idling, then at about 16 seconds in I rev it to 2.5 - 3k for a moment and then let it drop to idling again, at about 45 seconds through to 1m 3 seconds you can hear the mechanical twittering sound quite clearly. It dies off at the end of the recording. If I had continued to record it would have come back again.

https://dl.dropboxusercontent.com/u/314 ... tering.wav

Does anyone have any idea what that might be? It's got plenty of oil (in fact it's hardly used a drop since I bought it in Feb), the water level is perfect and it's not missed a beat for me at all.

Hoping you can help, all ideas appreciated.
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Re: Please listen to my Bongo - it's twittering at me

Post by wonkanoby » Wed Sep 17, 2014 7:14 pm

diesels are prone to number one manifold stud breaking and manifold warping and leaking
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ICBongo
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Re: Please listen to my Bongo - it's twittering at me

Post by ICBongo » Wed Sep 17, 2014 7:37 pm

Forgive my incompetence but is this a DIY job?

I'm OK at doing stuff if I can follow some instructions can you guide me with some detailed instructions please?

Also is it drivable without damaging anything?

Thanks, and I appreciate your help
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Re: Please listen to my Bongo - it's twittering at me

Post by Simon Jones » Wed Sep 17, 2014 8:40 pm

It does sound a bit exhausty which would be consistent with no.1 manifold stud being loose or broken. Have a look at the exhaust manifold where it meets the head and you'll probably find it's black with soot at the front of the engine where no.1 stud is. Is it DIY-able? I'd say on balance no if the stud has snapped in or close to the head. You may be lucky and just find the nut has come loose. Is it ok to drive? Yes, for short term but if the manifold continues to warp (which is why the studs snap) it will increase the chances of problems with the new stud and possibly even the manifold cracking when tightened under tension.

Factsheet here for you or your mechanic: http://www.igmaynard.co.uk/bongo/member ... nifold.pdf
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Re: Please listen to my Bongo - it's twittering at me

Post by Northern Bongolow » Wed Sep 17, 2014 8:56 pm

the metal sound towards the end sounds like this.

http://www.igmaynard.co.uk/bongo/forum/ ... ank+pulley
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Re: Please listen to my Bongo - it's twittering at me

Post by Northern Bongolow » Wed Sep 17, 2014 8:59 pm

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Re: Please listen to my Bongo - it's twittering at me

Post by ICBongo » Wed Sep 17, 2014 9:03 pm

Thanks for all the help - I will have a look and report back!
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Re: Please listen to my Bongo - it's twittering at me

Post by ICBongo » Thu Sep 18, 2014 1:44 pm

Ok, so I have had a look and I don't think it's the bolt. Here is a pic with the heat shield lifted up:

Image

I got a socket in to give the bolt a little tweak just to see if it was loose and it didn't appear to be. However I didn't give it much force as I didn't want to cause it to shear.

So I started it up again and put my ear right by the alternator (luckily I don't have much hair so no danger of getting it trapped!) and had a good listen and I reckon that's where the noise is coming from. I have to say there is never a problem with the battery, it's always very positive starting.

The belt feels nice and tight so I don't think need tensioning (but I could be wrong of course). Could it be that I need a new couple of belts or perhaps a new alternator?

Your thoughts and comments as ever are appreciated.

Ian
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Re: Please listen to my Bongo - it's twittering at me

Post by teenmal » Thu Sep 18, 2014 2:13 pm

You could get one of these or use a bit of brush shaft.

http://www.ebay.co.uk/itm/Automotive-Me ... 2579c345bb
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Re: Please listen to my Bongo - it's twittering at me

Post by ICBongo » Thu Sep 18, 2014 2:20 pm

Hi Teenmal,

Do you mean use this to listen to the alternator to see it it's making the noise or the belts?

Thanks.
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Re: Please listen to my Bongo - it's twittering at me

Post by teenmal » Thu Sep 18, 2014 3:05 pm

Yes you can use it to listen to the alternator bearings/adjuster bearings etc etc ,but I don't know how you could listen to the belts.

The sound that you are getting is in my opinion metallic. (bearing)

Is it more pronounced on the passengers side rather than the drivers side.
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Re: Please listen to my Bongo - it's twittering at me

Post by TheStinkyHippy » Thu Sep 18, 2014 4:25 pm

Mine had noisy alternator

http://igmaynard.co.uk/bongo/forum/view ... =3&t=66448

Doesn't sound much like yours though..

Final proof was to loosen the belt tensioner and remove the 2 belts off the alternator, and then spun it by hand.. and I could feel/hear the noise.
(Replaced it with a second hand one and all quiet again)
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Re: Please listen to my Bongo - it's twittering at me

Post by ICBongo » Thu Sep 18, 2014 6:59 pm

teenmal wrote:The sound that you are getting is in my opinion metallic. (bearing)

Is it more pronounced on the passengers side rather than the drivers side.
Yes I believe it is more pronounced on the passenger side. Do you think I might be looking at a new alternator?
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Re: Please listen to my Bongo - it's twittering at me

Post by pongobongo » Sat Sep 20, 2014 11:30 am

Check the intercooler pipe mount - mine sounded like that. Replaced this am.

Does it vibrate like mad when turning off?
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Re: Please listen to my Bongo - it's twittering at me

Post by ICBongo » Sat Sep 20, 2014 11:44 am

Hi pongobongo

My noise comes and goes, and no it doesn't vibrate when I turn off the engine. I had a good listen yesterday and had a go at alternatively loosing and tightening the alternator belt but with no audible difference.

Being a bit of a mechanical newbie - can you direct me to the intercooler pipe mount please and I'll check mine?

Thanks for all the help - really appreciated.
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