Since a couple of weeks I began the following practice: arriving home and not planning to use the car till the following morning, I lift it to the top position and then lower it to the bottom in order to "exercise" the system, particularly to lubricate the struts and work out the proverbially lean correctors. I do it just once and then turn off the car. The entire suspension has since become more soft and proper. However, within one week of such practice, I have to add LHM to the tank following the warning light on heavier acceleration or uphill, without any obvious leak on the path.
Without this lifting for another week, the LHM level stays stable.
I would like to understand what can cause the LHM loss on lifting to max height and also where can LHM "disappear" without dribbling on the path? Thank you.

When at full height a considerable ammount of fluid is pumped into the spheres to raise the car, so the level dropping is quite normal. Loss of fluid with no apparent leak is not as easy to explain, although I have yet to see an XM that doesn't leak fluid somewhere. Are you carrying extra weight in the boot? that will cause the level to drop as it requires more pressure in the rear suspension. The only other possible reason I can think of is that some air has been expelled from the system somewhere that has been replaced by fluid.

Peter.N.

Another reason for a low "LHM condition" is when the LHM is low due to topping it up in the tank when the vehicle is not at its highest setting. This is essential to get the correct amount of fluid in the system for all eventualities.
I think the regular use of the High/Low action seems to be a good idea to avoid any potential blockages.

A third possibility, when you are on full "up" you may have exposed a leaky part of the rams in that position and the lost fluid is filling up the normally empty return lines. Clutching at straws!

Derek

It would seem that the return pipes do not hold a lot of fluid. The only explanation I can think of for 'disappearing' LHM is one or more rapidly deteriorating spheres, which could have been exacerbated by the gymnastics.

The spheres have recently been checked and some of them replaced.
Strange and illogical. Thanks anyway.

You need only one failing sphere to create your problem. Just keep an eye on the level

Are you sure the lhm fairy's arent coming out at night and drinking it??
But seriously, since you seem to have had some work done on the system recently (spheres) i would say it could be air expelled by citrobatics as peter has already mentioned.
Peter, i have no leaks of any kind whatsoever on my xm, and before you ask yes the system does have oil in it

D

Since there are not other malfunctions related to this, I might just leave the things as they are and just leave the Citroen fairies drink their green potion as long as they keep troubles away!