awdinut

Leaving car in 'comfort' with 'jack mode' on produces only about 1/2 inch drop on the driver's front side. When I then tun on the ignition (but do not start the car) the car, and turn 'jack mode' off, I can get out of the car and get close to the left front wheel and hear air steadily escaping. And the car will lift up the half inch it was low, then air escapes and the car drops a half inch and immediately the car adds air from the air tank and lifts back up....and it just keeps cycling up and down like that.

When I start the car the compressor starts to run and cycle off with an air release pop that sounds like it is under pressure. And that pressure release from the compressor cycling repeats often as I drive. I had VCDS check for codes and there were two: LEAK IN SYSTEM DETECTED and SHUT OFF DO TO OVER TEMP. Both codes were date stamped in the last couple weeks.

And another thing, when I put the car in 'LIFT' I got the yellow and green warning lights and the car reverted to 'COMFORT' with 'LIFT" and 'DYNAMIC' greyed-out.

The shop says they have never seen anything fail except a strut. I have never personally had anything except a strut fail on a D3, and I dont recall anyone here on AW having a failure other than a strut, or a compressor burned out by a leaking strut...but, on the other hand, I have never seen symptoms such as this case. Every other time a strut went bad there was pronounced dropping on one side. I was ready to call the dealer and order a strut but I thought I would inquire here first.

dvs_dave

I think you have a leaky drivers side strut. Do the soapy water test and check the valve block for leaks whilst you’re down there.

ltooz_a6_a8_q7

Hello Audinut,
Logically, I don't think the scenario you have setting "Comfort" + "Jack Mode" is programmed... You should only put "Lift Mode" + "Jack Mode". Did you try that to see if it does the same thing? Should one be at the highest to insert the jack to jack up the car?
I think Dave's recommendation is the best, don't assume a $1500 part unless you know for sure it's really leaking, unless you. don't want to get dirty. Get 2 ramps, drive the car up, carefully, choked all rear wheels and handbrake securely (for not rolling), put the car on lift mode - pump it up fully. then put on Jack Mode Turn of the engine. Go under and start spraying... You should see the leaks if it does.
Cheers,
Louis

awdinut

In my view soapy water provides what you might term a 'false negative'' as a test procedure when dealing with struts. I have just recently seen a strut sprayed down at the shop and there were no bubbles what so ever. But, absent any other culprit, the strut was replaced and the leaking down on that side was solved. It seems there are just too many areas of the strut that can leak that cant be sprayed for that to be a reliable test procedure.

Not to say no one has ever seen bubbles, if the strut happens to be leaking from a visible/accessible site bubbles would be observed. But absence of bubbles would not exclude the strut IMO. And the fact that my car is only dropping one half inch is the part that doesnt fit the scenario I am familiar with. And whats up with holding COMFORT height (except the half inch) but not achieving LIFT height at all ?

Anyone know of a valve block leaking ? What part of them would be able to develop a leak ?

MP4.2+6.0

100% agree with you. Posts suggesting soap test on struts is definitive are assuming too much. It is just not. BTDT on mine. It did not bubble w soap. Flat out. Simply given the size of that dust cover alone, you just can’t soap in that area or anything covered by it, just to name one location it will come up short. Nor to some of the posts that say you can hear it would I rely on that either. Again, BTDT and inside a quiet closed garage space. And yes, after soaping all including valve block, I concluded correctly that mine was front right strut, but only based on it dropping very slightly faster on that side than drivers side. Maybe 1/2” difference only as it fell over 12-18 hours, so difference was subtle. No codes either. Thus, not a great feeling to buy a new strut when you can’t pin it down 100% and the drop difference side to side was little enough you wondered if you had it correct.

Back to OP, I would also soap test the valve block given symptoms described. Not necessarily the issue, but since that is fully accessible when undone from its bracket (at least on W12s), I do view that soap test as definitive for leaks. Still could have a switching issue among its solenoids though.

d6lc

I have a post going currently about diagnosing my suspension woes, I agree totally that the soapy water test isn’t perfect. Have you tried disconnecting the front sway bar?, perhaps the other side is holding it up to some degree. See my post, that seems to by my issue

dvs_dave

One corner dropping is the biggest giveaway. You're right on the soap test not being a 100% accurate fault finding method, but to discount it completely I would say is unwise as if you do get bubbles, that’s a 100% accurate diagnosis. It’s all about building up a picture of symptoms you can identify and using that information to make the most educated descision.

awdinut

I should have added that I replaced the passenger side strut just last month. So, while the current symptoms are not the same (other strut blew a nice definitive hole in the dust cover), having both struts fail with in a month or so of each other is an oft told tale...and now that I think of it, my last A8 followed that paradigm.

And having MP describe his past scenario of only dropping half inch etc makes me feel better about my decision to order a strut from Audi today. At least as good as possible when spending $1200 (or $1125 actually after Arnott buys my core for $75). But then there's the $200 I have to pay for installation. Well, at least the struts wont be hanging over my head like the sword of Damocles. Of course the bad news is the sword is not there because... THE SWORD FELL !! Ouch.

dvs_dave

Sounds good. For more conclusive proof, raise it up to lift level, put it in jack mode and then disconnect one of the front sway bar links. That will make the corner drop much more pronounced and be a dead giveaway.

ScottCNelson

I wonder if these people aren't went a try. Personally, I went with RMT and so far so good:

https://aerosus.com/audi/a8-d3.html