Whirring Noise

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elevan

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I'm getting a weird whirring noise, in short bursts, from under the bonnet. Mostly when driving quite slowly on winding or undulating country lanes and sometimes when taking my foot off the accelerator. Also immediately after stopping and switching off. It sounds like some sort of pump.
Any ideas?
 
What are you driving? may help
 
I'm getting a weird whirring noise, in short bursts, from under the bonnet. Mostly when driving quite slowly on winding or undulating country lanes and sometimes when taking my foot off the accelerator. Also immediately after stopping and switching off. It sounds like some sort of pump.
Any ideas?
Might help if you can record the noise please.
 
Not sure if I can record it. It's intermittent and on good roads doesn't happen at all.
 
N75 Moo valve ? around 2012 issue on 180s updated pipes and valves fix the issue on our 2012 180 SE could be that.
 
N75 Moo valve ? around 2012 issue on 180s updated pipes and valves fix the issue on our 2012 180 SE could be that.
N75 Moo valve ? around 2012 issue on 180s updated pipes and valves fix the issue on our 2012 180 SE could be that.
Moo valve sounds very likely. Have since found it elsewhere in the forum including a recording which is the noise I have. Never heard of a moo valve before today and now know why it is called thus. Very many thanks for your advice.
Good night.
 
It’s an easy DIY job, just order the OEM part (Pierburg).
 
My experience of the Moo (N75) valve was that it only Mooed on turning the engine off. This sounds to me more like the engine cooling fan which comes on when the air flow through the radiator is low, such as driving at low speed, and often runs on for a minit or so when the engine is turned off. When you next use the van be ready when you turn the engine off to open the bonnet and have a look. If it is the Moo valve get it fixed!
 
My experience of the Moo (N75) valve was that it only Mooed on turning the engine of
Ours did it both on the mooove and on stopping intermittently
 
I was told that eventually it can cause the turbo to fail. I have no first hand experience of this, I think I read this on the T5 forum. VW have a service fix for this on the T5 so I assumed it can't be nothing.
 
Thanks for raising this. My 2012 T5 140 has been producing a strange noise very occasionally for about 5 years. 'Mooing' describes it perfectly. Usually heard when decelerating. Could we have the technical term for the valve so I can ask my local garage to fit, please?
 
Thanks for raising this. My 2012 T5 140 has been producing a strange noise very occasionally for about 5 years. 'Mooing' describes it perfectly. Usually heard when decelerating. Could we have the technical term for the valve so I can ask my local garage to fit, please?
N75 valve. When I had mine changed the local garage said they could not do it as the replacement needs to be coded to the engine. True or false I don't know so VW Swindon did it for about £150. They said their was a VW fix so VW know about it.
 
I've got the mooing noise when engine switched off. I will have to do the replacement myself as my local dealer are people i wish to avoid as they provide poor service.
Can i order the valve with the new vacuum pipes, if so where please?(other than my local dealer)
Has anyone attempted this job on a 2.5 engine?
 
I've got the mooing noise when engine switched off. I will have to do the replacement myself as my local dealer are people i wish to avoid as they provide poor service.
Can i order the valve with the new vacuum pipes, if so where please?(other than my local dealer)
Has anyone attempted this job on a 2.5 engine?

Yes, I replaced it on mine (2.5, 130 engine). This was the part I fitted, you’d need to check the correct part for your engine number. Pierburg is the OEM (don’t buy a cheap copy), about £40 IIRC. Try Murray’s Direct. As long as you’ve got a socket set, it’s a really easy job. Watch a couple of YouTube videos which show you how to do it.

3437DB5E-7B09-46C2-A4F7-03696972FF35.jpeg
 
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Thanks, that's very helpful. What about changing the vacuum pipes, did you replace those also?
 
No, the pipes were fine. Just take care when removing from the old valve that you don’t damage them.
 
Great, thanks so much for your help. I see that on my engine the vacuum pipes don't generally need replacing unless obvious damage, however later models required a vacuum pipe upgrade. :thumb
 
Ordered Vv from heritage, checked engine number from log book first. Hopefully I'll receive it in the next day or so.
My Calli is a 2008 model so I can expect this with it's age.
Thanks again Elmo3 for your help...diolch.
 
Just to finish off what I started. Lookers VW in Carlisle subsequently diagnosed it as indeed the N75 valve and quoted £326.77 to fix it. But I have an extended warranty with Warranty Direct who paid the lot (apart from my £50 excess) with absolutely no quibbling. So job done and no more mooing!
Many thanks to the Forum for pointing me in the right direction.
 
Lookers VW in Carlisle subsequently diagnosed it as indeed the N75 valve and quoted £326.77 to fix it.

for a valve that's probably about 20 quid to the trade, and 20 minutes work!
 
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