Hi
I have 2003 E500 and today the rear end went down, both sides, so how i can know its the air spring not the air compressor and how I can find out which side needs to be replaced ?

 

Have a star diagnostic done and the exact cause will show up. A good indie shop should have this. I have one that does it free fro me here in Athens, GA. The problem with your car could be a number of things and as simple as a sensor or broken air line.

 

I would suggest you add this issue to 1000's of identical topics already on the forum.
SD scanning is nice option to start if you have it easy available, but not knowing if the message went off after few minutes, or stays permanently, I can only suggest the compressor/dryer service to start.
No air system likes water in subfreezing temperatures.

 

Yeah. I wouldn't assume for one second that it's one of the air springs. It might be. It might be the valve block, the controller, or a broken air line to the rear. It might be the compressor, although if the front is okay, perhaps not. You need to take it to an Indy that works on Mercedes sedans. There are a lot of them, and many are good. Even the Gulf station near me has a guy who works during the week at the dealer and on Saturdays at the station. He is good with all Mercedes, and has a STAR. No need to be trying to puzzle this out yourself.

There is a tendency on this forum to believe that a basic service station has never seen a Mercedes, and needs everything explained to them, and that is just wrong. My Indy (not the Gulf station) has worked on Mercedes for years, and knows exactly what to do. That I will walk in and say I want the Arnotts means only that he says, "Great. Do you want to get them or do you want me to order them?"

If it is the spring, get the Arnott solution. www.arnottindustries.com A vastly-quicker installation, and a great product. Partsgeek.com has the best prices on the Arnott stuff, with free shipping. I have the Arnott rear springs, which went in a few months ago. They work great, and having a new spring (like I mean the spring itself) in there has dramatically-improved the ride. Wish I had changed them out years ago. If it's the front strut, get the Arnott rebuilt ones, not the $1200 OE ones. The Arnott struts for the 4-matic (don't know if you have 4-matic) are a little hard to find these days; you may have to get them direct from Arnott on their web site, but they are still waaaay cheaper than the new ones. Another option is to send your actual struts to a place called Rebuild Master Tech, which you can find on Google. They will turn them around in a day and Fedex them back to you. (Again, this is just for the 4-matic struts if you ever need the struts. Partsgeek has a zillion of the Arnott rear spring replacements.)

PS To the original poster: Where are you that it's 2 degrees F outside at dusk?