Finding leak in air suspension

[Stuarta]

Anyone have any advice on how to find the leak?

I'm still a newbie A8 owner and all was well until this morning when I had the dreaded flashing icons - this is what vag-com said:-

Address 34: Level Control Labels: 4E0-910-553.lbl
Part No SW: 4E0 910 553 H HW: 4E0 907 553 F
Component: LUFTFDR.-CDC H06 4480
Coding: 0015510
Shop #: WSC 02313 785 00200
VCID: 2855E99BE263

3 Faults Found:
01583 - Leak in System Detected
000 - -
Freeze Frame:
Fault Status: 11100000
Fault Priority: 3
Fault Frequency: 74
Reset counter: 55
Mileage: 60487 km
Time Indication: 0
Date: 2011.12.05
Time: 14:38:24

01577 - Turn-Off due to Over-Temp
001 - Upper Limit Exceeded - Intermittent
Freeze Frame:
Fault Status: 00100001
Fault Priority: 4
Fault Frequency: 24
Reset counter: 95
Mileage: 61176 km
Time Indication: 0
Date: 2011.12.29
Time: 11:02:55

01400 - Suspension Level Control
002 - Lower Limit Exceeded
Freeze Frame:
Fault Status: 11100010
Fault Priority: 2
Fault Frequency: 2
Reset counter: 55
Mileage: 61581 km
Time Indication: 0
Date: 2012.01.15
Time: 11:27:51

I tried clearing the codes but they all came back straight away.

I'm assuming that the over-temp is due to the compressor being taxed to overcome the leak - question is, how to trace the leak?

[PsYcHe]

Possibly luck... Let it all cool down and listen at each corner to see if you hear it, otherwise it's garage time.

[snapdragon]

I would put some washing up liquid (or foamy car shampoo probably kinder) into warm water in a bucket and then use a beaker or such like to throw it over the pipes, dampers etc... Maybe an older household sprayer would be helpful too. If there is a leak, you should see cuckoo spit forming.

[Stuarta]

Seems to be sitting much lower at the front - so I'm hoping that'll narrow things down! Will try to have a look later today. Thanks.

[PsYcHe]

Fingers crossed it's something easy and not a blown shocker (though A8parts have them in).

[Stuarta]

OK - had a listen and can definitely hear something at the front - will need to wait for tomorrow to jack her up and have a look. Rear sounds fine.

Incidentally, I have often noticed a hissing noise from the front when getting out of the car and assumed that it was the system venting pressure on shutdown - I assume then that it's NOT normal?

[snapdragon]

Originally Posted by Stuarta

Incidentally, I have often noticed a hissing noise from the front when getting out of the car and assumed that it was the system venting pressure on shutdown - I assume then that it's NOT normal?

This is normal, it is compensating for the loss of passenger weight.

http://www.volkspage.net/technik/ssp/ssp/SSP_292.pdf

[PsYcHe]

Yep.. the hiss when you turn off is normal...

[Godders]

Originally Posted by snapdragon

This is normal, it is compensating for the loss of passenger weight.

http://www.volkspage.net/technik/ssp/ssp/SSP_292.pdf

I'm sure I read somewhere (Allroad SSP242, page 47 on - http://www.volkspage.net/technik/ssp/ssp/SSP_242.pdf) that the hiss on shutdown is to blow dried air back through the dryer (dessicant) in the compressor to 'regenerate' it.

[PsYcHe]

Could be... I thought it was just releasing the pressure in the system to reduce component strain.