normal to whine?

Technical questions and answers about the Mazda Bongo

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phildread

Post by phildread » Mon Oct 01, 2007 6:36 pm

Simon Jones wrote:It is normal for all gearboxes (auto or manual) will make some sort of whining noise, especially in 1st or 2nd gear. Other things that can add to the effect: rear (& front in 4WD) differential gears: this willl increase with road speed, or the noise from the turbo which increases with engine speed.

It's tricky to say what is normal, unless you can have a listen to someone elses. Is there anyone on the forum in your area that you could meet up with for a test drive?
thank you. that makes sense. you actually described the noise much better than i did! :roll: :lol:
my Bongo is a 4 wheel drive and turbo diesel. the noise occurs when i floor the accelerator (slip road for example).
phildread

Post by phildread » Mon Oct 01, 2007 6:37 pm

Captainsideways wrote:If it whines through all the gears it'll be the diff or transfer box if its a 4wd one.
not all the gears Capt, just when i accelerate hard.
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waycar8
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Post by waycar8 » Mon Oct 01, 2007 6:43 pm

Thats the turbo :lol: , nowt to worry about :wink: , some do. it some dont
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Ralph

Post by Ralph » Mon Oct 01, 2007 6:59 pm

if it's more of a whistle sort of noise than a whine it
most likely is the turbo
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Timnz
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Post by Timnz » Wed Jan 02, 2008 11:42 am

I have a whining noise which appears to be loud at 1500 and 2500 rpm, centred on these rpms, and still noticable if in neutral, can hear it when the van is stationary, but more noticable when driving as the engine is quieter. Doesn't matter if I accelerate or how much load is on it, ie driving up a hill. Any ideas?

The fact that if I put it in neutral when driving along, then accelerate to get the same revs ie 2500, but coasting and I get the same noise suggests it is the engine rather than the gearbox. yes?
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Timnz
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Post by Timnz » Wed Jan 02, 2008 11:46 am

it's a low pitched whine, and isn't belt noise, as I can lift the engine bay seats while driving, and the noise is no louder. seems to transfer noise into the cabin somehow. Manifold studs?
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helen&tony
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Post by helen&tony » Wed Jan 02, 2008 12:10 pm

Hi Timnz
I've got a similar noise....more a VVVVVvvv...you'll find that if it is the same, then it is the alternator. Are you sure it's not the belts? The noise is definitely not tansmission if you can ellicit it when driving and coasting as you say, but coasting at any more than a few KPH in neutral is not a good idea in an auto.
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Timnz
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Post by Timnz » Thu Jan 03, 2008 4:34 am

how could I test to see if it is the alternator? I had the belts replaced about 10000 km after I got the van, it wasn't making the noise then.. maybe the belts were too tight and now the bearings are starting to rumble?
Extra wear from having the fridge on ?
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helen&tony
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Post by helen&tony » Thu Jan 03, 2008 6:36 am

Hi
I suppose that you could run the engine for a few moments without the belts. I'm not saying it is the alternator ...just a guess. If you put a wooden rod on the alternator, and put your ear against the other end, you can also hear the noise conducted ....take GREAT CARE by moving parts. That's the old- fashioned way of sound tracing.
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Re: Whine

Post by mikeonb4c » Thu Jan 03, 2008 11:06 am

helen&tony wrote:Hi
I suppose that you could run the engine for a few moments without the belts. I'm not saying it is the alternator ...just a guess. If you put a wooden rod on the alternator, and put your ear against the other end, you can also hear the noise conducted ....take GREAT CARE by moving parts. That's the old- fashioned way of sound tracing.
Helen
Also using a length of hose as a 'directional microphone' is worth a try. Again, be VERY careful about moving parts and snatching (sounds rude :shock: )
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Post by bigdaddycain » Thu Jan 03, 2008 11:18 am

Could this "whining" sound simply be the sound of the turbo spooling up? (the rev range points to this) It may be worth checking that the air filter is sitting correctly in the airbox housing,and that the securing clips are correctly in place... This could explain an "induction roar" type sound.
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Post by Timnz » Mon Jan 14, 2008 3:17 am

definitely a new sound that has appeared in the last 5000km...
low pitched rumble developing into a full low pitched whine @ 1750rpm. obvious under load, and just when you back off the accelerator( arround these rpms.)
Had the cambelt, and all other belts replaced, and the water pump 10,000km ago.
Any ideas? driving me crazy..
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