[boonjh]

My 04 V8 with 175000Mi on it, started idling really uneven, multiple misfires on all cilinders.

O2 sensor upstream bank 1 was bad. I replaced all four O2 sensors.

Still get "System too lean" on both banks.
(I also know my catalytic converters are shot)

In the egine bay, there is a loud sucking sound coming from the little disc located on top and back side of the intake manifold, more to the driver's side. When I put my hand over its opening, (preventing air entrainment) then the idling improves.

Any ideas?

 

[Rsen99]

Pretty sure that is the PVC. I got one off of ebay and seem to be lasting.

 

[Odessa]

PVC .... it lets the engine breath correctly. .... Replace it.

 

[boonjh]

Thanks guys! Is it worth cleaning, or just replace?

 

[Odessa]

some people clean .... but you must have patience of a saint and a delicate hand like a surgeon .... otherwise you'll snap the lugs which hold the unit together

 

[nickyt]

If it is already sucking air, then it's dead Jim! Time for a new one.

 

[unitpump2013]

Does anyone know how the PCV works?

Does anyone know how the PVC works?

 

[noobytoogy]

How does a positive crankcase ventilation (PCV) system work? | HowStuffWorks

If you need a new one, best get a VW one - lots of people have bought duff PCV valves on ebay and gone the VW route in the end.

 

[unitpump2013]

How to check the pcv fail?

noobytoogy,thanks a lot!
But i am still wondering how to check my V8 PCV.How to make sure that the valve is a failuer or not?
Some tech man told me to open the oil cap when the engine was running to check,I just can not to make a judgement.

 

[noobytoogy]

You haven't described any symptoms.

 

[Scubacruiser]

PCV: Positive Crankcase Ventilation

A PCV valve simply allows pressure buildup in the crankcase to escape. The pressure buildup is caused by blow-by around the piston rings.

 

[Scubacruiser]

PVC: Polyvinyl chloride

The world's third most common synthetic material used to make pipes, bottles, etc.

 

[noobytoogy]

Ha! That's like the me always calling the MFD [the dash display] the MDF!!

 

[unitpump2013]

can i use 077 103 245B to replace my old PCV?

06 touareg v8 PCV type is 077 103 245B.Does anyone know can i use 077 103 245C to replace it which is for the VW Passart?I really do not knot the difference between 245B and 245C.
Thanks a lot!:smile2: