S_W222

I just noticed that one time after not driving my car for 3 days it seems to be setting a little lower and nicer than when I normally look at it. Doesn't seem to be a suspension (Airmatic) leaking issue as it's barely noticeable. For that reason, I started to monitor the height of the car after 12hrs, 24 and 48 hrs. I can tell u that overnight there is nothing or maybe less than 1/8 of an inch difference and then maybe after 2 days... I am talking about 0.25-0.5 or so but never in the inches range......
I assume everyone will say it'an Airmatic leak issue, but so far that car has been serviced and couple of check points including suspension were completed and there has been no concerns addressed.

I wonder if this is something you guys also notice (you have to be really picky to notice that, and leave it for >1-2 days not driven). I read couple of articles that the car sets lower overnight sometimes due to self-leveling feature? I also have to say that the spot I park at night is not 100% leveled, there is an incline of few degrees.

OnlyGerman

All four of my airmatic struts are new and I still notice the front lowers if not driven for some time. If it the car is slammed to the ground, then you have a issue.

S_W222

That makes me feel better. not it does not slam to the ground nor that it looked too low, it's one thing I noticed and when I monitored it i noticed the few millimeters or quarter-to-half of an inch difference after 2 days. The problem is that I do agree that this seems to be normal, especially that u also see this issue on your car, but I just want some mechanical explanation for what's happening. I mean if there is no leak, why do these cars get slightly lower overtime (especially front)? is this a feature or what?

konigstiger

A certain amount of suspension drop due to thermal contraction is normal and should not be regarded as a malfunction. Approximately 30 mm of suspension dropping in cool temperatures is within design parameters.

S_W222

30 is almost 1 inch, wow....... is there a reference somewhere or is it written in the manual? Thanks for the feedback, just carious to know if this is common on all cars or if's written somewhere.
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OnlyGerman

Are you under any kind of warranty?

S_W222

Yes I am, but it doesn't cover the Airmatic/suspension now. It's only for the engine and transmission and some other parts.

I am literally talking about 0.5 inch maximum difference, and it's 35F now in the morning compared to warmer temperature in the 60-70 when I parked it. If this is something that you all notice, then am not too worries about it. Just wanted to see of other users are noticing the same....

konigstiger

Noted on several MBUSA bulletins.

S_W222

NOTE:
A certain amount of suspension drop due to thermal contraction is normal and should not be regarded as a malfunction. Approximately 30 mm of
suspension dropping in cold temperatures is within design parameters

I just found the statement above, that was copied as, in this document below:
https://f01.justanswer.com/73bbchevy..._code+5507.pdf

konigstiger

222 relevant bulletin, design allows for 2 cm = 20 mm = approximately 3/4 inch drop.

PNBLWZD

I have noticed my 550 suspension airs up a little after being parked for a week or so, and also new ones sitting on the lot do this as well. Pretty sure it’s normal.

hyperion667

Normal!

Utopia Texas

There is hardly ever information in the manuals on technical specs on these cars. The average owner only puts gas in the tank and never checks the tire pressure until the light comes on. I am constantly amazed at how many folks come on to these forums after owning a car for 2-3 years and admit they have never looked at the manual that comes with their vehicle.

S_W222

Agreed!

S_W222

Update:
I've been taking measurements (distance between the lower edge of the rim to the fender) over past 2 days:

Baseline: 27.25 inches (day 1 morning)
after 12 hours: 26.75 inches (day 1 night )
after 24 hours: 26.75 inches (day 2 morning)
after 36 hours: 26.75 inches (day 2 night).

So far it looks it sets lower by 0.5 inches overnight (day1) and then hopefully it stabilizes.... i'll wait one more day tomorrow to confirm. If it stays at 26.75 inches it means it just the thermal contraction of air in the airmatic system.

Wolfman

Konigstiger has is spelled out. 3/4” is normal and that is what I experienced over time as well.

I always thought the car looks better that way. As soon as you start it is back to normal.

hyperion667

S_W222

Updated (48-hr data point) measurements for today:
Distance between the lower edge of the rim to the fender) over past 3 days:

Baseline: 27.25 inches (day 1 morning)
after 12 hours: 26.75 inches (day 1 night )
after 24 hours: 26.75 inches (day 2 morning)
after 36 hours: 26.75 inches (day 2 night).
After 48 hours: 26.75 inches (day 3 morning)

Experiment is done. This confirms the air contraction theory for the W222 AIRMATIC system, during first 12 hrs only before it stabilizes, with around 0.5 inches due to air contraction. This happens when ambient temperature of air inside suspension drops to 30-40F or lower, yielding a lower air density and thus a smaller air volume in the suspension which causes the car to set lower.
**For the record, these measurements were taken at temperature of 32-35F. I expect the contraction to increase by another 30% based on air density at 15F or lower, meaning another 0.25 inch for a total of 0.75 inches at colder temperatures such as 20F or lower.
Based on this, 0.75 inches of height difference is within design parameters, however, for those who experience more than 1-inch of height difference overnight, i would encourage them to test for any potential air leak especially during summer or when temperature is not that low.

hyperion667