C5 Hydractive 3+ Suspension Issue

[rusty-pie]

Few weeks ago I have purchased a Citroen C5 Tourer 2.0 HDI 160 Exclusive Auto made in January 2010 with around 60000 miles on the clock, equipped with the Hydractive 3+ suspension.

I am very happy with the car, but every time I go over a speed hump or a steep crest on the road, above a certain speed depending on the steepness of the back step of the hump, I can hear a loud bang coming from the front end when the front suspension extend after the hump apex, as if either the wheels were dropping down rather than following the profile of the road, or if the suspension had reached the end of the extension travel (topping out).

I have driven over the same humps at higher speeds with cars with conventional steel springs and they could cope without problem with the same humps. This is my first Citroen, I was wondering if someone with a better knowledge of the Hydractive 3+ suspension could tell me if this is this normal with this system or it is a sign that something is wrong?

Thanks in advance.

 

[paul.h]

Welcome to the forum.

 

What speeds are you trying on the humps, is it enough to almost lift the car in the air ? Does the car raise and lower ok using the switch ?

 

We have a 2007 C5 and find it gives a smoother ride over humps than a steel sprung car but would not want to go over about 20 mph on a gentle hump and less on one with a steep approach. Afterall, the aim of the speed humps is to slow the traffic.

[rusty-pie]

Hi, many thanks for your answer.

 

The suspension goes up and down normally when operating the switches, and the four corners bounce up and down when pushed by hand.

 

The noise happens at speeds consistent with the shape of the bump, I am definitely not trying to go too fast on them; 20 mph on a shallow, long hump (5 to 10 cm high, 2 m long or more) down to 5 mph on tall and short pillow shaped ones. It also happens at around 55 mph on a sharp crest on the road during my commute.

 

The reason why I ask the question is that as soon as I bought the C5, I noticed straight away that driving over humps at speed I was used to with other cars caused the suspension to make that noise. My previous car was a Audi A6 Avant with factory fitted lowered sport suspension, so my term of comparison is quite at the opposite end of the scale in terms of suspension comfort level, therefore I suspect that my perception of how the suspension should react could be biased. (I bought the C5 specifically for its unique comfort btw :-) ). On the other hand I have driven (and have been driven as a passenger) at least 5 to 10 mph faster with other cars on the same humps without problems........

 

I have the feeling that the front end may be bouncing up so high after the initial compression that the wheel either drops down skipping over the descending part of the hump, or reaches the end of the extension travel when extending further; is that normal with such a soft suspension when driving relatively fast over a hump? Is that the same symptom that makes you say that your C5 “would not want to go over about 20 mph on a gentle hump and less on one with a steep approach�

 

I bought the car from a main dealer (non Citroen) with a full warranty so I could bring it back to them for an assessment of the condition of bushes/joints etc. Will they be able to troubleshoot the Hydractive suspension without having had a specialized training on this system, and mainly is there any risk of them causing any damage working on it?

 

P.S. I have posted the same question on another dedicated forum to hear as many opinion as possible, apologies if I repeat myself! :-)

[paul.h]

I would go for the dealer check since your suspension does not seem right. My 20 mph is not based on bangs/other noises just the possibility of damaging the car. Maybe you could ask the dealer if they would support you asking a Citroen dealer to check the suspension.

[coastline taxis]

Have you got the car set a the correct height or are you carrying any heavy loads when it happens

[Parkesie]

Sounds like a problem i had where the bottom bearing on the hub carrier has failed. Often called the lower ball joint or a frim joint.

 

To check send suspension up jack up each wheel and rock wheel top to bottom. If someone can do this while you watch the bearings it should be easy to spot the duff bearing.

[rusty-pie]

Hi I am back after sorting out a boiler breakdown that took priority over the car..... :-)

Have you got the car set a the correct height or are you carrying any heavy loads when it happens

The car is riding at the standard heigh not carrying any load.

 

I have jacked up the suspension and lifted the front wheels, and tried to rock the wheels up/down & left/right but cannot feel any looseness other than a little play on the steering arm at the left wheel, but I recon that should not be the cause of the knocking.

 

After I have lowered the wheels, with the suspension still fully up, I have bounced the front end and it I can hear a faint knock when I bounce the left front corner, I guess that that could be a sign of a worn bushing or joint; I think I am going to take the car to the dealership and see what they say. I hope they will authorize me to take the car to a citroen dealership under their warranty. Will post the outcome later on.

 

Hijacking my own thread: I have also noticed that when I accelerate hard from low speed the auto box stays in 2nd or 3rd gear almost up to the redline and does not shifts up for a few second after lifting up the accelerator, is that normal? Maybe I should have posted this on a separate thread..... :-)

Edited August 21, 2014 by rusty-pie

[Johndouglas]

Have you looked at the drop link joints.    They shouldn't be worn at 60000 miles but might be.

[rusty-pie]

Have you looked at the drop link joints.    They shouldn't be worn at 60000 miles but might be.

 

How do I check if there is play in the droplinks?

 

I went for a ride this afternoon to try and work out what kind of bumps cause the suspension to bang. Humps with a sharpish corner are much worse rather than rounded ones.  It seems that is predominantly speed bumps which make both wheels to bounce simultaneously, the car is instead much smoother and quiet driving over deep potholes at higher speeds where only one wheel is affected. Not sure if this means that the problem is in the anti roll bar (which rotates significantly over speed humps) or the actual suspension linkage. 

 

Car is booked in for a test ride with the dealer tomorrow; is there anything I should warn the mechanic about the hydractive suspension, other than not to raise/lower the suspension when the car is jacked up?

[Johndouglas]

Raise the suspension before jacking up.

[rusty-pie]

I went for a road test with the mechanic and he too found the noise unusual, although he is not familiar with the hydractive suspension so he wasn't sure if it is normal or not on that system. Service manager is seeking authorization from the warranty department to let me take the car to a citroen dealership.

 

I live in Bournemouth and the local dealer is Penton in Christchurch, has anybody had any experience with them with regard to the hydractive suspension?

 

I am not familiar with this suspension either; I wonder if because the suspension is so much more compliant (and in my opinion less dampened) than conventional steel sprung ones, they cannot cope with speed humps at speeds that instead would be OK with other cars?

[Parkesie]

Check that lower bearing. Sounds exacly like what mine was doing..

[rusty-pie]

Check that lower bearing. Sounds exacly like what mine was doing..

 

Hi, I did try the way you suggested in your previous post but could not feel any obvious play other than a little bit in the steering, ie trying to twist the wheel left/right, but I wondered if a little bit is normal there.

There was no apparent looseness trying to twist or move the wheel up/down, but I guessed that the anti roll bar would stop the wheels from moving as when one wheel is up the other compressed down so the anti roll bar is heavily loaded.

 

How did you spot the failed bearing exactly?

[Parkesie]

Takes a good amount of force rocking the wheel top to bottom.

 

 

Little vid of what your looking for.

[sta7cool]

Hi,

 

I am noticing the same problem. Bought a 2nd hand C5 tourer 2011 (2.0 HDI, 163 HP, exclusive, automatic) with 130k km. Loud knock (actually a BANG) occurs on both sides in the front when I drive over a speed bump. The exact movement that causes the knock is acctually front suspenssion extension move. It doesn't knock on compression or small bumps, only on a fast extension move. It seems that a certain threshold of "extension speed" has to be reached for knock to occur. From there on, regardless of the speed, loudness is the same. 

 

Otherwise, susspension works perfectly. To bad I can't take advantage of superb floating ability over speed bumps as it becomes so loud. 

 

Anyone solved the problem?

[rusty-pie]

Hi,

 

I am noticing the same problem. Bought a 2nd hand C5 tourer 2011 (2.0 HDI, 163 HP, exclusive, automatic) with 130k km. Loud knock (actually a BANG) occurs on both sides in the front when I drive over a speed bump. The exact movement that causes the knock is acctually front suspenssion extension move. It doesn't knock on compression or small bumps, only on a fast extension move. It seems that a certain threshold of "extension speed" has to be reached for knock to occur. From there on, regardless of the speed, loudness is the same. 

 

Otherwise, susspension works perfectly. To bad I can't take advantage of superb floating ability over speed bumps as it becomes so loud. 

 

Anyone solved the problem?

 

 

Hi, this is exactly what happens to me. Specifically, on series of shallow humps (about 2 m long and 5 cm high) on my daily commute the critical speed is 18 miles an hour, and I can drive on the same humps at 30 miles an hour without any discomfort or fear of damaging the car. It happens only where the change of slope is quite sudden, ie flat hump with two ramps on each side rather than more rounded ones. I would not even call it a noise, but rather feels like a knock on the front end as if the car was being driven over a shallow 90 degree pavement step.  I tried with the suspension in sport mode and the phenomenon is slightly reduced.

 

Anyway, the garage where I bought the car authorized a diagnostic at their expense from my local citroen dealer. I took the mechanic for a test drive and then they put the car on the ramp for a couple of hours. I spoke afterwards with their senior technician which seemed competent and knowledgeable about the hydractive 3+ system. He reported that they had inspected all the suspension components and anti-roll bar joints and could not find any fault or looseness/play. He also checked for updates of the suspension ECU software but no update was available for my car. He recons that this is a behaviour peculiar of the hydractive 3+ suspension system on C5 and C6 models. Unfortunately there was no other car in the garage at that moment with those suspension to let me try a different one on the same humps.

The mechanic deems that it could be that the wheel momentarily loses contact with the surface of the hump and the knock is caused when the wheel hits again the road. This is consistent with the feeling of dropping down a step, but I am puzzled that the wheels on a modern car can lose contact with the road at such low speeds.

 

Could it be possible that the suspensions are not capable of extending fast enough to follow the road profile, either by design or because of some sort of fault in the system itself?

 

Or maybe when they extend so rapidly one or more components in the system are temporarily unloaded and then suddenly loaded back causing the knock?

 

I would really like to try another C5 with Hydractive 3+ suspension over the same humps and compare. If anybody is in the Bournemouth area and fancies popping in for a cup of coffee and a quick drive down the road please let me know! :-)

 

On a side note, I have to say that both the dealership where I bought the car (Westover Hyundai in Bournemouth) and the Citroen dealer (Penton in Christchurch) offered an excellent service.

[Mike O.]

My last C5, the facelifted December 2004 2.2HDi SX Auto Wagon (Estate) produced the very knock on some specific speed humps at certain speed. So does my new October 2013 C5 2.0HDi Exclusive Auto Tourer, but to a lesser extent, I think.

I will test drive it over these humps tomorrow and report again.

To me it is caused by the front suspension reaching the end of its rebound travel and the bump stops being too hard and not progressive enough.

 

We discussed the car's engine 'revving its head off' a few months ago.

I have since learned not to press the accelerator so hard, which eliminated the problem.

[rusty-pie]

Hi Mike, I am curious to hear about your road test.

 

To me it is caused by the front suspension reaching the end of its rebound travel and the bump stops being too hard and not progressive enough.

 

I did think about that at first when it happened on a very high hump (over 150 mm high) which would justify the suspension reaching the extension travel (topping out), but then it happened again on long and shallow humps, 2-3 metres long and 50 mm high, flat top with a steep ramp around 300 mm long each side; I doubt that 50mm would be enough to reach the suspension maximum extension.

 

Other possible explanation would be that the suspension cannot react fast enough in extension and the wheels skip over the ramp rather than following the profile of the hump, and the knock is caused by the wheel making contact again with the tarmac..... Initially I thought that this would be in contrast with the fact that in sport mode the critical speed is increased (ie the knock is reduced at the same speed) because the stiffer suspension should on the contrary be slower to react, but on a second thought I realized that in fact the opposite may be true: closing the passage to the third sphere, the two operating sphere must work at a higher pressure to support the same weight of the front axle - 2 times the diaphragm surface for the sport mode rather than 3 for the comfort mode, hence the nitrogen pressure must be 1.5 times higher in sport - and therefore the higher pressure would cause the suspension to react faster and follow better the sudden change in direction of travel of the wheel. Any thoughts?

 

Can you please post a link to the discussion about the engine revving?

[Mike O.]

Hi rusty-pie,

 

There was a weak knock at 40 kph and none at lesser speeds.

The road sign suggested 25 kph.

 

The revving was discussed under: 

Automatic Transmission Misbehaving

Started by Mike O., Jun 03 2014 09:55 PM

 

Cheers,

 

Mike O.

[FreddyVTS]

Hi, I'm writing from Italy, in the italian Citroen Club Forum we discussed so much about this "loud bang" you are talking about, some of us spending weeks of diagnostics from various citroen's dialers, the response was even the same: no problems, no faults, probably a genetic issue of the hydractive3+ system...

Below the entire discussion ;-)

Saluti from Sicily!

 

http://www.citroen-club.it/forum/viewtopic.php?f=81&t=1476

[paul.h]

Thankyou for this. Google did a reasonable translation. Something I read in the posts was that in sports mode, the knock is not as bad, so something for people to try.

[Xsaradope]

I drive mine in sports mode for this reason and the dealer just said " you would think it would make more noise in sport mode"  Clueless considering how many people complain of this same fault.

[aspire_helen]

When  I bought my second hand c5 2.2hdi in 2003 at 9000miles I too was rather surprised by how much the suspension "knocked" over bumps, rough roads, potholes etc, especially from the rear.  The dealer looked at it and found nothing wrong.  16 years and 150,000 miles later the suspension is still going strong (with the odd weeping seal).  However, this was a common concern as Citroen's solution was to add improved noise absorption material under the rear seat.  Citroen's advice to dealers was : Level 1 - assure customer everything is OK.  Level 2 - if customer is still concerned, carry out mod to add noise absorption under rear seat.  In other words, the Hydractive3+ suspension is not as smooth over bumps as Citroen would wish us to believe,even  from the earliest days of the C5.

 

I learned from that experience that Citroen will always try to fob off the customer at first.  Therefore, it pays to persist.  For example, I complained of uneven wear on the rear tyres at 15000miles.  Citroen initially accused me of "taking corners too quickly" - can you believe it? After I pressed them further (along the lines of "you cannot be serious"), they stated that a batch of rear sub-frames had been drilled misaligned.  They replaced the subframe and gave me two new Michelins under warranty.  20,000miles later it proved to have had no discernible effect on the uneven tyre wear.

[coarist]

Hi All, having re-read the postings many time over, I have this theory. If the suspension knocks when it is on an extending stroke, there could be trapped air in the hydraulic circuit of Hydractive.

To test the theory, there are a few checks. Has LDS fluid reservoir enough fluid? At any time did fluid loss happen? Joins on the hydraulic lines, are there significant wetting indicative not only of leak but also air sucked in? Are the linking pipe work in good regular shape not been smashed by objects such as stones?

And if the Hydractive is due for service which is a fluid change, the work may be able to purge the trapped air in the affected part of the circuit.

Small amount of air in the hydraulics will not show when in compression, but even a tiny pocket on fluid side of the damp gate can expand indefinitely (relatively speaking) causing the bang when the strud hides the limit of the stroke. Air on the other side, on the contrary, does not adversely compromise the damper function in this manner.

[coarist]

Further developing the assumption that trap air needs purging, suppose that is the case, then try this:

(1) make sure there is sufficient LDS fluid in the reserviour.

(2) Lower the car fully then raise the car.

This is to create circulation to hopefully purge the air out into the reservoir. The discharged air will eventually diffuse into the atmosphere.