bagpipingandy

i think an airbag leak, the leak is related to the height of the car, which is linked to the speed, as your speed increases the car lowers from 3-2, as the car lowers the leak is more aggressive,

if you park the car (ignition off) and leave it at level 1 does it sink?

if so park the car at level 3 (ignition off) does it sink?

if it sinks at level 1 and does not sink at level 3 you have leaking airbag, which would give the symptoms you are seeing

best regards

andy

Leondrew

Thank you. Your suggestion worths a good try. But as you have seen, there are so many possibilites, which directly means it is not easy to maintain the air suspension system in good condition for a 100,000 mileage allroad,it needs attention from every place. I don't want to keep spending money and time on this system, I have ordered 4 coil springs from Arnott, and will start to replace the air springs this afternoon. Hopefully I wish I can finish the installation later today or tomorrow.

Leondrew

I haven't tried parking at level 1 because I don't like level 1. I wish the car to be a SUV, so I prefer to have higher level most of the time. But based on my freeway driving experience, it seemed it was much harder to maintain the car at level 1. Anyway, I will just replace the air springs with coil springs. Both money and time are precious to us. Thanks.

Leondrew

Actually, my car dropped to the lowest level for 4 times, three of them happend when I was driving to ski resort and I had to drive on freeway everytime. I once made a joke to my wife that the outside temperature so low so that the air inside the bag were frozen. Based on your experience, maybe it is not a joke.

Romario

Belive me, root cause is a valve unit malfunction. If you want fix it in one time, renew valve unit and forget about falling. I'm sure it so easy than replacing spring coils and other things.

bagpipingandy

hi, this potentially gives more evidence it is a leaking airbag, if the car were to drive around all day at level 3 or 4 with no sinking but it is when you go higher speeds on the free way the car will lower to level 2 or level 1 and if it sinks everytime in this condition, its a leaking airbag or 2!!, , whatever end was sinking had the leak.

coilovers will certainly fix that problem for you but an airbag would probably have cost less.

i hope the install goes ok, at least it wont sink anymore

regards

andy

Romario

If necessary to check air bag leakage you can use soap water. Doesn't matter level of air suspension. If air bag leaking, it will leaking anytime and only speed of falling will be "show" size of hole.
If suspension falling during driving and keep level (2nd, 3rd or 4th during night time and longer) major issue is valve unit malfunction, only. Dirt and ice inside of valve unit to interfere closing itself.

bagpipingandy

a leaking airbag is determined by height, small-medium leaks don't leak at high levels. The perished rubber (not holes) is always found on the lower bend of the rubber airbag, but when the car is physically higher the perished part is on the higher flatter area and the cracks are closed, but lower the car the perished part is now at the fold and the cracks open and air leaks out ussually quickly, soapy water will show this but only with the car at level 1, if you jack it up and cover with soapy water it will show no leaks, you must simulate low levels such as level 1, where it will always leak, if a leak present.

valve blocks can cause issues but in this case especially as the OP keeps the car high and all is ok but when going fast the car lowers the cracks open and so it sinks points to a leaking airbag. Doing a test parking at level 1 & then at 4 would prove this, sinking at level 1 everytime and no sinking at level 4 is 100% an airbag perished/leak, even a perished airbag can sit for days at level 3-4. But park at level 1 and it will sink in 1/2 hour or overnight depending the size of perished area.

looks like he has a solution but it is now a non-allroad!!

regards

andy

Romario

"Russian bears" which driving Allroads during 6 months winter time investigated all issues of air bags. We know all about perished rubber. But......
I've explain what necessary to do for testing and I'm sure - if topic starter has no issues every morning, his has no leaking air bags and root cause is malfunction of valve unit.
P.S. For more comfortable testing of air bags by soap water, you could remove wheel and install car to a special legs, but it must be kept under the arms of front and rear suspensions.
Best regards, Roman.

Leondrew

Hi guys,

I love you all, your are all nice. I like this forum.

As you have seen from the posts to my topic, there are a few possibilities. According to the local delear, the two froint air bags were leaking and the compressor was not working properly (>$3,500 to fix). In my opinion, the valve and the sensors might also contribute to this, and the two rear bags might also begin to leak in the future. When I first bought this car, the self-leveling system looked really cool, but now I am tired of having the car sinking gradually to the lowest level to bring the yellow warning light on. If you were driving behind me when that happened, you might laugh because the car in front of you were bumping so obviously...

So after some online search, I decided to get away the air suspension problem permantly, and thus ordered four coil springs from Arnott. I watched video from youtube, and began to replaced the springs since yesterday. The video seemed so easy but when I actually worked on it there were so many problems especially I don't have a good jack and a warm garage (but I do have a pair of standing jacks to protect me). I did it in a public parking lots while it was cold. I was planning to finish the installation in six to eight hours, but unfortunately the screws were rusted and took a lot of efforts. I spent another three hours this morning, and finally replaced all of the four air springs. The car now looks exactly like sitting at level 2, and I felt the coil springs were a little bit stonger than air springs (someone said softer, I don't care that much).

From allroad to non-allroad, even though it is not that fancy now, and I had some unpleasant experience, I still like my car, and I get to know it better.

Lastly, the check engine light is on after modified some wires from the control unit according to the installation instruction from Arnott, I went to autozone and had a technician diagnosed for me, and it reported an error saying there is something wrong with communication,probably from those new wires. I checked my wire connections, couldn't find any issues. I will call the company to figure out the problem. If you guys have any suggestions to fix that as well, it will be really helpfull.

Thank you all.

Leondrew