W221 Airmatic

[mbenz1]

Hi Guys

Just a quick question. My dad is interested in looking to buy a 2006/2007 or 2008 S320 CDI V6 Diesel.

Could anyone shine some light on the reliability of the Airmatic suspension in the W221, and any common faults? Also, what are he typical repair costs if the main parts of the system fail?

Finally, what should be oticed regarding the suspension, when test-driving a S320 CDI etc...?

All help appreciated as usual.

Thanks

 

[stumpy1]

Generally it is a reliable system but I did have a brand new one which had a non-fixable fault and the car was replaced.

 

[Borys]

Above 100k miles will cause problems
Changed two struts in past, very annoying

 

[C43AMG]

I have done 105,000, have not had a problem and have not heard in the business ( Chauffeur Business ) of it being a common fault.

 

[Borys]

You're very lucky then
I bought a lemon

 

[ItalianTuneUp]

Front airmatic struts eventually leak air. At least on W220. The hot engine area seems to shorten the life of the front struts, so it's usually the front ones that leak, almost never the rear struts. The epoxy eventually cracks and air escapes, causing the car body to sag when parked up. Another common point of failure with airmatic leaks is the airmatic valve block above the compressor. A pair of new OE Mercedes front struts cost about £1500, so it's good to know what to look for.

 

[mbenz1]

Thanks guys for your comments. So its after 100k miles where problems can happen.

 

[ItalianTuneUp]

Around that. Arnott Inc, who make replacement airmatic struts, quote the lifetime of the struts at about 80,000 to 100,000 miles.

 

[ItalianTuneUp]

Also, airmatic valve blocks are about £300 to replace, and the compressor costs something similar too, iirc.

 

[C43AMG]

I have not heard of it being a common fault on any mileage,

 

[ItalianTuneUp]

Well, I don't know how common this fault is, but if you do a search, I think you will find many forum posts on this subject.

I had to research this topic myself and I found many tales of woe. Anecdotally, allegedly even MB acknowledge they know about airmatic front strut leaks. If you do a search, look at the pics of cracks that appear on the top of the front strut seals. I have personal experience of this failure, and have read many, many posts in search of clues as to what was going on with my car's air suspension system.

When it's working though, it gives a lovely smooth ride.

 

[whitenemesis]

Always bear in mind, people generally come onto forums to post problems. If one does a search for a particular issue, don't be surprised to find many hits!

How many owners of AIRmatic equipped cars drive around all day every day with out an issue? We'll never know 'cos they don't join up and post

 

[ItalianTuneUp]

Very true.

However, all moving parts will eventually fail, and these components take a pounding, so it's normal they will eventually fail, like any other component, no? And if the approximate design life of airmatic front struts is about 100k miles, then it's normal that people driving cars with lower mileage are not likely to see this issue, thus not complain. Older cars though, that's a different matter.

As one of the aggravators of front strut demise appears to be the hot engine compartment, the type of driving likely makes a difference. Stop/start driving probably won't cool the engine compartment so well, thus more heat...shorter strut life? Or travelling over bad road surfaces is probably likely to shorten life...etc.

I can imagine drivers doing lots of motorway miles with good engine compartment airflow and smooth (ish!) motorway road surfaces will probably have their struts last longer, but I'm just guessing now.

 

[mbenz1]

Guys, much appreciate your comments. I can understand that airmatic parts will fail... Its just the big repair and labour costs thats a worry.

 

[V12]

It may be due to the age difference but there is anecdotal evidence that the airmatic on the W221 is more hardy than the W220...

Simon, a repair kit for the compressor on your W220 is around £25.

They are expensive to maintain at dealer prices!

 

[ItalianTuneUp]

Thanks Ricky, it seems like the compressor is OK for now, as the car rises quickly if I push the raise body button on the dash, but I'm pleased to hear there is a cheap repair kit for the compressor, for when it fails. I'm glad to hear that W221 struts are beefier than W220 ones.

It was the valve block that was leaky, and that was replaced, so all is good now (with new front struts - ouch!)

For mbenz1, there is also a repair kit for airmatic front struts which costs about £100 per strut. If this works, it is cheaper than buying new struts, but MB don't seem to like to advertise this kit, but you can find the part number if you search.

Also, it is wise to check the airmatic system before buying. Push the 'raise body' button on the dash to make the body rise. If it rises quickly then it would appear that the airmatic compressor is working correctly. Knowing what I know now, I would always check the airmatic system on a car I was considering in the morning, first thing before it has been started up, and on a cold morning. The reason is that, for some reason, cold seems to exacerbate airmatic leaks, and if there is a substantial leak occurring, you are almost certain to see the car body sagging (or the rear rising sometimes). Tip of the day

Here's some pics of cracked front struts to know what you're looking for:

Front Strut Seals Cracking! How much time do I have? - MBWorld.org Forums

http://mbworld.org/forums/attachmen...d1268762123-front-struts-leaking-img_0067.jpg

http://www.benzworld.org/forums/att...edes-airmatic-shock-disassembled-airmatic.jpg

Happy hunting!

 

[ItalianTuneUp]

Again, for mbenz1, if possible, give the car you are considering buying a soapy water leak test. Spray the soapy water onto the tops of the front strut seals. Spray over the whole area where the cracks are shown in the photos posted earlier. Also, if possible, spray soapy water over the valve block (it has about 4 or 5 airmatic air lines coming out of it) adjacent to the airmatic compressor. Then press the airmatic 'raise body' button on the dash. If leaks are present then you will see small bubbles forming on the valve block or front strut seals.

 

[mbenz1]

Thanks Ricky, it seems like the compressor is OK for now, as the car rises quickly if I push the raise body button on the dash, but I'm pleased to hear there is a cheap repair kit for the compressor, for when it fails. I'm glad to hear that W221 struts are beefier than W220 ones.

It was the valve block that was leaky, and that was replaced, so all is good now (with new front struts - ouch!)

For mbenz1, there is also a repair kit for airmatic front struts which costs about £100 per strut. If this works, it is cheaper than buying new struts, but MB don't seem to like to advertise this kit, but you can find the part number if you search.

Also, it is wise to check the airmatic system before buying. Push the 'raise body' button on the dash to make the body rise. If it rises quickly then it would appear that the airmatic compressor is working correctly. Knowing what I know now, I would always check the airmatic system on a car I was considering in the morning, first thing before it has been started up, and on a cold morning. The reason is that, for some reason, cold seems to exacerbate airmatic leaks, and if there is a substantial leak occurring, you are almost certain to see the car body sagging (or the rear rising sometimes). Tip of the day

Here's some pics of cracked front struts to know what you're looking for:

Front Strut Seals Cracking! How much time do I have? - MBWorld.org Forums

http://mbworld.org/forums/attachmen...d1268762123-front-struts-leaking-img_0067.jpg

http://www.benzworld.org/forums/att...edes-airmatic-shock-disassembled-airmatic.jpg

Happy hunting!

Again, for mbenz1, if possible, give the car you are considering buying a soapy water leak test. Spray the soapy water onto the tops of the front strut seals. Spray over the whole area where the cracks are shown in the photos posted earlier. Also, if possible, spray soapy water over the valve block (it has about 4 or 5 airmatic air lines coming out of it) adjacent to the airmatic compressor. Then press the airmatic 'raise body' button on the dash. If leaks are present then you will see small bubbles forming on the valve block or front strut seals.

Thanks for these two peices of vital information, just seen those posts now. My dad has just purchased a W221 S320 CDI 08 with full MB Service History. The car seems to raise and lower without any problems.

I will try the soapy water leak test. What are the front strut seals and what is a valve block. Are they right behind the wheel?

Also, I am a little dissapointed with the ride comfort... Wheel/Road vibrations and small bumps seem to be very noticeble in the cabin, since they can be felt on the floor, however, when accelerating the car seems to become much smoother and big road bumps seem to be dealt very smoothely by the suspension.

The car has RUN-FLAT tyres and the wheels are 18" (genuine M-B wheels)... would run-flat tyres or 18" wheels cause vibrations and small road bumps to be noticed in the cabin by any chance??

Thanks guys.

 

[V12]

Yes to run flats...they are awful.

Suspension bushes can make a big difference to the feel of small imperfections in the road.

 

[mbenz1]

Yes to run flats...they are awful.

Suspension bushes can make a big difference to the feel of small imperfections in the road.

Ok. In that case when the tyres need changing, will definately go for non run-flat tyres. IMHO I would rather have a smooth ride instead of run-flats... Its pretty suprising that the Airmatic system is not able to give a smooth ride when using run flats...

What are suspension bushes? How would one know if they need changing?

Thanks.