Mooo valve noise

[Simon enderby]

Having looked through the forums I think I have diagnosed the strange noise that intermittently keeps occurring in our Cali (2011,140bhp), the moo value.
However, we also have a 2nd noise that sounds like a bee stuck behind the steering column in the area of the speedo. Has any one had this accompanying noise with the mooo noise?

 

[Steve Fuller]

Hello, my 06 van has a small whirring noise behind the dash after stopping the engine, it las several seconds but has no apparent detrimental effect, I think it could be vacuum, from the heater flap controls, dissipating.

 

[VW Guru]

Hi there was a modification to the vacuum pipes the T5 pre 2010 had to have the N75 (moo valve) replaced but problems after that, T5gp had a problem venting ambient pressure and requires modified vac control hoses fitted to the N75 and Egr cooler change over valve

 

[Simon enderby]

Do you think this would be causing the bee type noise that we are experiencing?
The bee noise occurs when we are driving not once the engine has been turned off.

 

[VW Guru]

Do you think this would be causing the bee type noise that we are experiencing?
The bee noise occurs when we are driving not once the engine has been turned off.

Yes it can create a noise during normal driving normal during engine load changes ie off and back on the throttle and also during gear change. The only other thing that creates that buzzing noise is the dash insert under some loads it resonates. My suspicion is the noise is more than likely the vacuum control pipes though.

 

[BillyCasper]

At 18,00 miles, my 2 litre BiTD has developed a growl when accelerating between 1 and 2k RPM.

Does this sound like the Moo valves/pipes fault?

Regards


Sent from my iPhone using Tapatalk

 

[AlanC]

In a word, Yes

Alan

 

[BillyCasper]

In a word, Yes

Alan

Ta, I'll bring it up at next service when pump and belt will need doing. I'm assuming it's not urgent.

 

[AlanC]

Ta, I'll bring it up at next service when pump and belt will need doing. I'm assuming it's not urgent.

No, not urgent or damaging, just annoying.

I had mine done when the cam-belt and water pump were replaced. A much quieter drive home and hasn’t reoccurred since.

I am told the rubber pipes that connect the pressure relief valves to the turbos are replaced with an upgraded silicon type.

Alan

 

[VW Guru]

No, not urgent or damaging, just annoying.

I had mine done when the cam-belt and water pump were replaced. A much quieter drive home and hasn’t reoccurred since.

I am told the rubber pipes that connect the pressure relief valves to the turbos are replaced with an upgraded silicon type.

Alan

Hi @AlanC the pipes are replaced for the same rubber compound how ever the routing is changed with a different vent to allow the vacuum system to be vented much easier.