Checking Level of LDS

[pi14]

Dear All,

I have the following issue. My C5 X7 2017 was bought as the used car so I do not know the history of any maintenance of the hydro suspension. Last weekend I wanted to check the oil level.
I set the suspension to the lowest level with the button from inside the car. Opened the LDS tank under the hood but there was no fluid visible.
Then I depressurized suspension using DiagBox and during this procedure some LDS run out of the tank.

Does it mean that there was too much LDS in the system?
Or maybe I did sth wrong?
BTW how often one should change the LDS fluid? I know that some claim there is no need of this, like not changing the oil in the manual gearbox, which I think is not proper.

[GiveMeABreak]

Fluid should be between 'a' & 'b' and checked on the lowest setting.

LDS does not need changing normally, so is up to you.

[pi14]

Thx Marc for the reply.
I've seen the picture.
Any idea what is incorrect in my case? On the lowest setting there is no fluid visible according to the picture. But after depressurizing there was some leakage out of the tank?

LDS does not need changing normally, so is up to you.

Thx!

[GiveMeABreak]

Ok, so let me put it this way...

Officially the LDS tank level is measured when the hydraulic system is fully depressurised using the diagnostic tool. This ensures the maximum amount of LDS possible is returned to the tank.

As customers don't normally have access to a diagnostic tool to do this, they can't fully depressurise the system, so if the car is put on the lowest setting only when checking and topping up the LDS, there is going to be slightly more fluid in the system. So it follows that if the tank has been topped up previously using the lowest suspension only setting, then the next time the hydraulic system is totally depressurised using the diagnostic tool, you will get some fluid leaking out as the tank slightly overflows.

[pi14]

Dear Marc,

Thx again for the explanation. But to make it completely clear to me it should be done following:
- depressurize the system
- make the LDS fluid level in the tank according to the picture you attached.

Having more LDS may cause only some leakage through the tank like it was in my case after depressurizing the system. And generally it should not be a problem.
Not sufficient amount of LDS could be more problematic. Am I right?

[GiveMeABreak]

That's correct, also make sure the vehicle is on level ground before measuring.

There is some volume of air left in the tank for movement of the fluid as required. Never over-fill the tank or you can cause it to explode at the seams. That's why it's very important for garages to observe the correct position of the suspension if raising the vehicle off the ground where the wheels will be hanging unsupported! If the suspension is not raised to the highest point before and the LDS cap not removed, then the weight of the vehicle crashing to the ground when lowered can cause an uncontrolled return of the fluid to the tank and blow it.

Have a look here where we have produced some labels that you can download and print off to stick near the tank for mechanics:

viewtopic.php?t=62058

[pi14]

Thx Marc for the clarification.

Have a look here where we have produced some labels that you can download and print off to stick near the tank for mechanics:

viewtopic.php?t=62058

Great, thanks. Repeating important things is never to much.
Best

[coolerl]

The fluid levels should be checked with suspension depressurised (ideally), but as James says, put it on the lowest suspension level and wait for it to fully lower. The following diagram shows the levels for a C5 X7 - the BLUE being the maximum fill level and the ORANGE the minimum level.

Hi Marc,
I performed a double check of the LDS today and I am a little bit confused

With suspension on the lowest setting, the LDS fluid level is a the minimum mark as per your description above.
However, if I depressurize the system, the fluid level rises almost to the point of over spilling

Should I remove all the fluid and have it at the highest mark with the system depressurized?
Knowing the size of the talk, that would be removing 1L or more.
Would that be correct?

Thanks,
R.

[Kees]

Marc is no longer on the forum, but you are right, there's to much LDS in the tank, and you should remove the lds until the highest pont, if you use the diagbox to pressurized the system, or if you put the car in the low position, then you should see the LDS just at the bottom.

[coolerl]

Marc is no longer on the forum, but you are right, there's to much LDS in the tank, and you should remove the lds until the highest pont, if you use the diagbox to pressurized the system, or if you put the car in the low position, then you should see the LDS just at the bottom.

Thanks Kees!
I am asking because there is quite a big difference in how low the car is on the lowest setting and how low it is when the system is depressurized from diagbox.
On the depressurized system, the wheels almost touch the body of the car.

Having that in mind, I thought that there should be a difference in the oil level between the lowest setting and the depressurized setting.

[Kees]

This is correct, and also why I described both procedures how to check the level.
But the best way is to depresses the system with the diagbox.
I see in my earlier post, there's a fault, it must be, depressurized, not pressurized, sorry, the spelling checker make this mistake