Citroen XM Forum

Dieselman wrote: Sat Oct 25, 2025 1:36 pm Your car is a sinker, so expect it to.

The hydraulic warning light can indicate either pressure or the reservoir level. The level is easy to check: raise the car to Max and observe the orange mushroom in the sight glass, which should be between the two red rings.

It would be unusual for the system to not create pressure, unless there is air being drawn into the suction pipe between the reservoir and pump. Check the hose is tight on the spigots, by attempting to twist it.

If the regulator cuts in and out at less than 30s intervals either the accumulator sphere is short of gas, or the system is leaking internally. the brake "doseur valve" is the most common reason for internal leakage, possibly due to a partially seized bell crank stopping the valve returning to fully off.

the connector you queried is the accelerator lever sensor for the Egr valve, which only operates at idle/low fuelling conditions.

That's a relief that it's supposed to sink then

& The light must be pressure, when I did the quick fix on the strut return line I filled the tank up as it was almost empty
I tried the pipes earlier and they all seem tight so I'm not sure where air would be getting in?

&& The "pssh" sound I hear goes every few seconds, but it'll stop if I say turn to go round a corner, then when I carry on straight it starts again
Where is the doseur valve located and is there a way to create if it is the issue?
& Or How can I tell which sphere is out of gas to sort out?

TigerHunter wrote: Sat Oct 25, 2025 5:24 pm The first thing I would do is lower the car to the minimum height, detach the hydraulic oil tubes from the LHM reservoir, remove it and wash it well with gasoline. There are two filters to clean. Before reattaching the houses is important to try and fill the hose that feeds the pump.
The appropriate moment to change the LHM fluid. The system needs approximately 4 liters of LHM.
The next step would be cleaning the height correctors.
As Dieselman says above your car does not have an anti sink valve and relative sphere. So it's a "sinker".
Also you have a single circuit hydraulic pump. So the suspension should react very quickly.

PS: The EGR should open also when driving on constant speed at low regimes. It has entirely ecological purpouse.
I wouldn't reattach the vacuum house.
It's important though the EGR valve is completely closed. Otherwise you would lose power.
When you remove the intake. Clean it well internally.

PS2: Does your car have an DIRAVI steering rake?

PS3: The spheres have nothing to do with the hydraulic pressure or the rising of the car.
The car must be soft on all four angles and one should be able to lower it by hand. If a sphere is low on pressure or with broken membrane The car runs rough on the respective angle.
When a membrane breaks , the sphere fills up with LHM entirely and the hydraulic circuit loses approximately 400 ml of LHM.

Do all pipes need to come off or can I just pull the top bit of the tank that holds the filter and leave all the pipework attached to it?
Also where's the second filter?
& Do the hight correctors just come off or are they piped into the hydraulics?



Do certain model sink then?
& My suspension definitely doesn't react quickly
Had to wait like 4minutes earlier for the front to raise


&& Where is the EGR valve actually located? I can't seem to find it


& I'm not sure if I have a DIRAVI steering rake, how can I tell?


&& Is there a way to tell if the sphere is buggered? The suspension still feels bouncy still on all four corners
I did have to fill the tank up with lhm and it was almost empty but I put that down to the leak I had

Themasteryeti wrote: Sun Oct 26, 2025 2:22 am
Do all pipes need to come off or can I just pull the top bit of the tank that holds the filter and leave all the pipework attached to it?
Also where's the second filter?
& Do the hight correctors just come off or are they piped into the hydraulics?

Just take off enough pipes to lift the top (and filters ) clear of the tank (but that is most of them).
You will see the two filters when you lift the top.
The height correctors are plumbed-in.

Themasteryeti wrote: Sun Oct 26, 2025 2:22 am
Do certain model sink then?
& My suspension definitely doesn't react quickly
Had to wait like 4minutes earlier for the front to raise

All early XMs are sinkers, all late XMs are non-sinkers, but the changeover happened gradually as updated engines were fitted. The first was the 2.5 TD in 1994, the last was the V6 in 1997.

4 minutes is much to long for a sinker, I would say 30 seconds should be enough. How long does it take for the suspension to rise when the engine is strated forst time for the day?

Themasteryeti wrote: Sun Oct 26, 2025 2:22 am
&& Where is the EGR valve actually located? I can't seem to find it
& I'm not sure if I have a DIRAVI steering rake, how can I tell?

I don't know about EGR, but I expect it to be connected to the exhaust manifold.
Only V6s with the PRV engine were fitted with DIRAVI.

Themasteryeti wrote: Sun Oct 26, 2025 2:22 am && Is there a way to tell if the sphere is buggered? The suspension still feels bouncy still on all four corners
I did have to fill the tank up with lhm and it was almost empty but I put that down to the leak I had

The best way to test spheres is with a sphere pressure tester, but if you don't have one, you can compare the feel of the suspension with a car with known good spheres.
When you say the suspension is bouncy, does it feel like the suspension is rock-hard with the tires bouncing over bumps? If so, then you definitely have spheres with low (or no) pressure.

All of the bleeding (returning) hoses are rubber and plastic made and with the years they deteriorate and become pretty fragile.
So the less you twist and move them, the better is.
That's why I did recommend to detach them from the cover of the cannister.
Also. if you remove the cannister it's much easier to wash the filters.

I think you have possibly three issues with the hydraulic system.

Firstly raise the car to maximum height and check the fluid level as indicated. Please confirm the orange mushroom is between the red rings.

The in tank suction filter could be blocked, requiring a clean out. This has been covered in a number of threads but the images have gone, so I'll cover it here.
To clean the reservoir and filters I don't disconnect any pipes, unclip and unbolt the reservoir at the front edge, remove the clamp over the filter unit, lift the front of the reservoir to tilt it backwards while lifting the filter unit out. With enough tilting, the unit will just clear the reservoir top, but be aware a full reservoir may spill some fluid, so either be prepared, or draw some fluid off before performing this task.
Find a container to rest the filter unit in. The return filter is retained by a wire S clip and simply unclips, the suction filter is held in with a bayonet fitting.

Return filter
Suction filter Clean with white spirit or petrol.

Empty and clean the reservoir out, refit the filters and the filter unit, refill with fluid, open the 12mm bleed bolt, start the engine and wait for air to be purged, then tighten 12mm bleed bolt.

You may have air leaking in due to either low fluid level, or loose suction pipe connections.
The system could be leaking internally, or externally.
Assuming not externally the most likely reason for excessive leakage is a stuck Doseur valve. If the linkage is fully returning the system may have sludge in it causing sticky valves. If so, flush with either the proper Hydraurincage. If it was my car I would be tempted to use new Lhm and 1/2 litre of white spirit for 2,000 miles, then change for fresh Lhm.

The spheres may be flat.
The rapid cycling of the pump/regulator indicates the accumulator sphere is flat/ruptured, or system leakage is excessive. The accumulator provides the reserve of pressure, so if flat, when the system is under high demand, such as steering, the pump can't keep up with the flow rate, so system pressure falls.
Your options are either fit known good spheres, or find someone to test and recharge any good ones you have. Pleaides at Sawtry are probably the closest to you, but some members on here do have such equipment, though it's easier if you take already removed spheres to them, rather than them fitted to the car.

The best method of finding is there is an internal system leak is to disconnect each reservoir return pipe in turn and observe the flow rate, which should be minimal.

Giving a definitive answer is not possible as we need more information from you. If you start checking and reporting back we can help you more.

To confirm, your car is a sinker and no Rhd Xm was fitted with Diravi steering.

xantia_v6 wrote: Sun Oct 26, 2025 3:32 am Just take off enough pipes to lift the top (and filters ) clear of the tank (but that is most of them).
You will see the two filters when you lift the top.
The height correctors are plumbed-in.

I get ya! Take it i should undo the de pressurize bolt before removing these then

xantia_v6 wrote: Sun Oct 26, 2025 3:32 am
All early XMs are sinkers, all late XMs are non-sinkers, but the changeover happened gradually as updated engines were fitted. The first was the 2.5 TD in 1994, the last was the V6 in 1997.

4 minutes is much to long for a sinker, I would say 30 seconds should be enough. How long does it take for the suspension to rise when the engine is strated forst time for the day?

Learning more about these ars everyday!
The rear takes like 20/30 to raise up front will take a few minutes, if I stit there and move the suspension up and down one after the other the front does get a bit quicker but not by alot

xantia_v6 wrote: Sun Oct 26, 2025 3:32 am

I don't know about EGR, but I expect it to be connected to the exhaust manifold.
Only V6s with the PRV engine were fitted with DIRAVI.

That would make sense

xantia_v6 wrote: Sun Oct 26, 2025 3:32 am
The best way to test spheres is with a sphere pressure tester, but if you don't have one, you can compare the feel of the suspension with a car with known good spheres.
When you say the suspension is bouncy, does it feel like the suspension is rock-hard with the tires bouncing over bumps? If so, then you definitely have spheres with low (or no) pressure.

Unfortunately I don't know of anyone near me to compare to
&& I'm not really sure, I'm so used to driving a excessively lowered car with rock hard suspension so it's hard to tell with this car

TigerHunter wrote: Sun Oct 26, 2025 8:53 am All of the bleeding (returning) hoses are rubber and plastic made and with the years they deteriorate and become pretty fragile.
So the less you twist and move them, the better is.
That's why I did recommend to detach them from the cover of the cannister.
Also. if you remove the cannister it's much easier to wash the filters.

Thanks for the heads up! I'll try my hardest not to contort the hoses to much

Dieselman wrote: Sun Oct 26, 2025 9:43 am I think you have possibly three issues with the hydraulic system.

Firstly raise the car to maximum height and check the fluid level as indicated. Please confirm the orange mushroom is between the red rings.

Yep it is in-between the rings

Dieselman wrote: Sun Oct 26, 2025 9:43 am The in tank suction filter could be blocked, requiring a clean out. This has been covered in a number of threads but the images have gone, so I'll cover it here.

Apriciate that! As a complete citroën novice pictures help so much

Dieselman wrote: Sun Oct 26, 2025 9:43 am You may have air leaking in due to either low fluid level, or loose suction pipe connections.
The system could be leaking internally, or externally.
Assuming not externally the most likely reason for excessive leakage is a stuck Doseur valve. If the linkage is fully returning the system may have sludge in it causing sticky valves. If so, flush with either the proper Hydraurincage. If it was my car I would be tempted to use new Lhm and 1/2 litre of white spirit for 2,000 miles, then change for fresh Lhm.

Does the whole system need to be drained for this or can I get away with just emptying the tank and using this method?

Dieselman wrote: Sun Oct 26, 2025 9:43 am The spheres may be flat.
The rapid cycling of the pump/regulator indicates the accumulator sphere is flat/ruptured, or system leakage is excessive. The accumulator provides the reserve of pressure, so if flat, when the system is under high demand, such as steering, the pump can't keep up with the flow rate, so system pressure falls.
Your options are either fit known good spheres, or find someone to test and recharge any good ones you have. Pleaides at Sawtry are probably the closest to you, but some members on here do have such equipment, though it's easier if you take already removed spheres to them, rather than them fitted to the car.

If I bought new spheres online do they come already gassed out of curiosity?
But that pleaides looks to only be half an hour from me so that might be a shout as I think I've fixed the issue with my other car so if be able to run them over if so

Dieselman wrote: Sun Oct 26, 2025 9:43 am The best method of finding is there is an internal system leak is to disconnect each reservoir return pipe in turn and observe the flow rate, which should be minimal.

Don't suppose you'd have a picture/diagram depicting which pipes are return pipes and which ones go to where?

Dieselman wrote: Sun Oct 26, 2025 9:43 am Giving a definitive answer is not possible as we need more information from you. If you start checking and reporting back we can help you more.

I do appreciate the help from everyone! I know problem finding is never easy when everyone's spread across the country trying to piece together what little bit of information I can give
I will definitely try the above tho and come back with updates!

For system pipework diagrams see this thread, particularly post #2. viewtopic.php?f=13&t=10291

Also a workshop manual diagram for Rhd Pipes at reservoir;
1. Pump suction hose
2. Steering return
3. Brake Doseur and ABS return
4. Leak off pipe for steering, suspension rams, height correctors, security valve.
5. Height corrector return
6. (Dirass) Hydractive electrovalve return. (Diravi) Steering and suspension electrovalve return.
When changing the fluid to flushing agent you need to fully empty the reservoir and ideally clean the filters then once hydraulic pressure is restored you should bleed all four brakes to ensure the flushing agent makes it into the brake circuit, which are dead ends.
Bleeding Xm brakes is easy.
Run engine, set to Max height, block brake pedal down, remove each wheel in turn and bleed the brake.

New spheres are gassed and ready to fit. Just be sure to buy the correct ones for each part of the car, as accumulators and Hydractive rigidity regulators don't have dampers built in, suspension spheres do.
Sizes, pressures and dampers vary depending on the model they are being fitted to. If you with to go down this route we can help with choice. I would do that, as it will work out cheaper than having a specialist supply and fit and you know the car then has known good spheres, leaving the old ones to be tested and re-gassed if they are still serviceable.

Again, fitting your own spheres is easy when you know how.

I've just remembered your car is Hydractive-2, so the most common reason for internal system leakage is the electrovalves are leaking, which is commonly due to split O rings.
See Posts #4 and #5 of the previously linked to Hydractive training material thread.

Thanks for the info!

Sorry for the noob question but what are the electro valves? Is that what the spheres screw into?

&& I'm starting to think it'll be either that or the pressure regulator orings gone as I've come into work this morning and they're a very obvious oil slick on the floor where I was parked yesterday