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Valve Block Failure? Entire right side low, left side at max height
Hi,
I have what appears to be a possible valve block failure. I started my 2011 GL450 this AM and was greeted with a really loud hiss from the rear. I look at the driver side rear and it's flat. The compressor runs and hissing continues as if it's trying to balance the car out.
The end result after several cycles is as follows:
1) Driver side rear spring pumped up to max.
2) Driver side front air spring is maxed.
3) Valve block no longer clicking to adjust. Doesn't appear responsive anymore when you open the door to reset the air suspension while the engine is running.
4) Entire passenger side of the car sits significantly lower than the driver side.
Thoughts are welcome. I checked the fuses, attempted to disconnect and reconnect with no success. Suspecting a dead valve block, mileage now at 161k with no known replacement prior.
Pictures below for details:
Driver Front:
Driver side Rear
Passenger side front
Passenger side rear
Last edited by Uranium238; Dec 22, 2023 at 06:17 PM.
There's a loud hissing sound from the back when I opened the car door after unlocking. Definitely not a slow leaking hiss. The hiss goes on for 2-4 seconds and stops. No quiet hiss either after that indicating an individual air bag leak.
Driver side doesn't appear to have any holes at all given the height of both the front and rear on that side. Problem is on the passenger side.
I should let everyone know that all air springs and shocks have less than 10k miles on them. They are also Bilsteins.
The ride height button is not raised which leads me to believe is valve block related too... but does a failing valve block do this?
I know when one air spring is bad, the car will attempt to compensate for the loss of air and redistribute. I had a bad rear air spring once on the driver side, and the airmatic system attempted to equalize the air on both rear springs until I replaced. I don't know if airmatic system will redistribute air on one side of the car between front and back...
As I understand a valve block, the module has many solenoids that open or close to release air and distribute. Doesn't look like this is being done for the right side. I "THINK" the loud hiss I heard under the car relates to the airmatic attempting to inflate the already maxxed driver side rear air spring.
I am ready to buy the part. I found a Genuine Mercedes valve block.
Last edited by Uranium238; Dec 22, 2023 at 07:15 PM.
Valve block ordered. Whether or not it fixes it, I have no record of it ever being replaced. Preventative counts.
Springs on driver side are harder than fans waiting for Pamela Lee's autograph. Passenger rear is sagging like Betty White while the front is slightly lower than normal...'
Started the truck up shortly after taking the pictures. I could hear very loud hissing on passenger rear and a low hiss on the driver side. I jacked the rear up and found a massive hole in my passenger rear air spring!
The driver side rear is hissing too. There was no hiss before on the driver rear. But it must have blown out too.
Could a bad valve block cause this too? These are NEW air springs.
Looks like you figured some of this out already, but...
Valve block is in the front of the car - any hissing from the rear has nothing to do with the valve block. Hissing in the rear is either the bags, the remote air canister or air lines. Most common is leaking bags... which you have now found.
The front sagging doesn't look "completely" Betty White. It could just be the way the weight is being transferred since the rears are blown.
I wouldn't do anything else till you get the new rear bags on.
See if the arms move easily by hand - disconnect them and move them.
Maybe someone else will chime in, but I don't see how height sensors would cause the bags to pop - I mean, if they were way out of whack, you'd notice that. You can read the sensors with some code readers.
Could just be a bad set of bags - hopefully they'll stand behind their product.
Well, some thing overinflated them, and I just possible that the sensor arm have been reversed or over traveled so that the inputs to the system are out of whack and the compressor is trying to inflate a bag that’s already inflated.
I would as blownV8 said, examine the sensors for smooth travel, and that they are all bending the same way
But yeah, when you have hissing from the back of the vehicle, there is absolutely a hole there, excess pressure is normally vented off in the passenger front wheel Arch by the intake.
A mistake we can all make with this system is to assume it acts as it should or reacts to a leak/malfunction in a predictable way. Unfortunately it doesn't. I've had a few problems with mine and what appears to be an unusual issue has always turned out to be a leaking airbag.
A mistake we can all make with this system is to assume it acts as it should or reacts to a leak/malfunction in a predictable way. Unfortunately it doesn't. I've had a few problems with mine and what appears to be an unusual issue has always turned out to be a leaking airbag.
You have to be methodical, just as with all mechanical diagnoses. When you have an electrical problem, the first step is to make sure the battery and alternator are both nominal. With the air suspension, one first has to verify that all air springs are not leaking and that the pump is working normally, regardless of the codes.
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