Strange noise

[Nickrs4.2]

Hi I've recently brought a rs4 avant I keep hearing a release of air noise as if a prv valve was going off. I believe it is coming from he rear left of the boot and have stripped the boot lining out to try and chase. There is a blue pump with hoses going to it in the bottom left corner? Does anyone no what it is for? Also there is a hose missing from this but I cannot locate a hose to be attached to it? Any help appreciated regards

[nij]

The air release sound is probably just the exhaust valves. You most likely to hear it when stationary, pressing the S button to turn off Sport mode, the vacuum is used to close the valves. The blue tank is there to hold vacuum for the exhaust valves, but not sure about the missing line.

[R1RS4]

If you have valved exhaust flaps in your rear boxes, check the hoses are in place

Just lay under the back of the car and look at the outside of the back boxs and if they are valved they should have single rubber hoses going into the valves sounds like one or both have the hoses missing

[Nickrs4.2]

Thanks for the replies. I can confirm I have a valved exhaust system. On the actuator on top of the air tank for the exhaust valves if the hosetail facing towards the front of the car is ment to have a hose attached? As only to out of the three horsetails have pipes on them on my car. Thanks in advance