Alexchrisro

Hello again dear colleagues and first of all please excuse me for initiating yet another thread about the air suspension on the cayenne 958.
A little background story, so in 2020 Jan i bought a 958 diesel. This was the best vehicle I ever owned, no problems at all, it currently has 230.000 miles on the clock. Runs like a dream.
However i saw some strange behavior on how the air suspension operates.
When is summer time and outside is very hot for a couple of days( 40C) after a couple of days of sitting, the back of the vehicle starts to sag, it did this three years in a row but I always checked if the suspension raises and lowers and it did it without any problems. Also i checked the nitro in the accumulator to a local workshop and they told me there is no problem with the air suspension.
This year however it started to lower the front(did not matter the outside temperature), after two days of sitting, when i open the drivers door the compressor kicks in and raises the vehicle back to normal position. Also if i try to raise the suspension to the highest setting it says: "not possible"... but if i drive the car for a couple of minutes the compressor kicks in to fill de accumulator (i guess) and everything is back to normal and the cars rasies to the highest settings without any problems.
I tried to go to an air suspension workshop but the folks there told me that everything is ok, i have 118-125l nitrogen in the accumulator and there is no error code stored.
Yesterday i locked the suspension but this morning it lowered a bit(about half an inch).
My question is... how can i diagnose this, i know is not normal,. If i go again to the suspension workshop the compressor fills in the accumulator and the suspension is working perfect and the diagnose on the workshop shows that the system has the correct level of nitrogen/air. Another strange thing is that once the compressor runs for about 1-2 minutes after i start driving the vehicle then it stays off, last week a drove about 800 miles and the compressor didn t kick in to fill the accumulator with air.
i am thinking the problem could be the block valve? What are your thoughts? Where do i start?
I don t think it is a good thing to leave it like this even if does not store any code and the suspension operates as it should.


Thank you very much for your help and excuse my bad english.

virkdoc

Something is leaking? Check for leaks from the bellows...and soapy water is your friend.

TyreReviews

My question is how do they think there's 125l of nitrogen in the accumulator if it's been leaking for years? Seems more likely that it would be full of atmosphere.

Mine is similar, my RR strut has been leaking since I owned the car, it only leaks if I leave it in anything but low and it leaks slowly. More recently it's not been able to get to the full height. I've probably worn the compressor out too.

It's a shame replacing the air bags is such an expensive process, and quite specialist for in home servicing!

Alexchrisro

I am sorry, i expressed myself rong, they did not told me that the acumulator has air or nitrogen, they just told me that on their diagnose shows 118- 125l when they cycled the suspension up an down and that everything is ok and as long as it stays at those values i shouldn't worry.
So far i am keeping an eye on the car, since yesterday with the air suspension locked it went down about half an inch and it stayed that way through the day.
I l check again tomorrow.
i am tempted to leave it like this until it throws an error chasis fault or something. but i don t want to ruin the compressor.

TyreReviews

That makes more sense

People seem to think the compressors are made of cheese so it's likely it will die before your car throws too much of an error. That said mine has been dealing with a leak for at least 2 years and it still lifts the car.

You can buy pretty cheap bag replacements from ebay / AliExpress that people have had luck with, and it seems you can use an icarsoft to withdraw and readd the air to each strut so you can service them yourself, I'm just not sure on the exact process yet. I plan on trying to do my rears myself one day.

One day.

Someone also suggested trying a top mount repair as they often leak from there. Similar amount of work though.

https://www.ebay.com/itm/37377737380...Bk9SR8z19dG-Yg

Alexchrisro

Thank you for your answers, I l keep you guys updated on how the fix will turn out.
Today it lowerd again half an inch, there s definitely a leak in the sistem.

Alexchrisro

Ohh and another question, if one bag is leaking the other will sag a little to if it is on the same axle?

RAudi Driver

Man I just might have to go into the rebuild air shock business. I've got 2 more months before I go back to work. Might not be a bad gig.

Alexchrisro

From where i am i think it would be a little far away )) ( Romania, Europe)

TyreReviews

Ripking

you’d make a killing. Arnott can’t even keep their own crappy struts in stock.I hate my air suspension and I’m going to dump the car soon because of it!

Alexchrisro

Found the culprit. Left top shock mount leaking. Used soapy watter and saw bubles on the top. I will change the top mounts.
Thanks everyone for the help, i l keep you guys up to date with the repair.

mafpolo

I have a 2015 CD without air suspension. My 1998 Range Rover air suspension started with one failed bag, but eventually the air suspension did fail. Replaced it with a traditional suspension kit.....couldn't tell the difference. My Lexus LS Ultra Luxury edition also had air suspension that failed. I converted it to coils and shocks....and the ride and handling improved. I have been looking at 2019 and 2020 Caynne's, and the vast majority on the forum advise to get the air suspension, because the standard suspension on the 9Y version is lousy. Many also claim that the air on the new Cayenne's is reliable. I like a good firm ride, and the idea of the ride quality is appealing, but air suspension scares the you know what out of me. Also, the service manager told me he (not saying its impossible) is not sure how a conversion would work, because the air suspension is tied into the computer system, and the car would be consistently looking for the air suspension to change the ride height.... so fault codes, etc.

p.s. Although not for sale not for sale until I find something I want, there have been some people who have reached out and expressed interest in a low mileage 958.2 CD, but aren't interested once I tell them I don't have air suspension.

TyreReviews

Somedays I wish I didn't have air (or most days) however when it works, it is really nice. I'm pretty sure eurowise do a coilover conversion for the 958 now, I'm not sure if they have a defeat device for the errors though.

dapopa9

@Alexchrisro did you ever find the answer to this? I have the same question. My guess is that, yes, it would cause the other spring on the same axle to lower a bit as the computer tries to keep it level.