A Front Suspension Sigh

[Eddyf]

When I shut down my late 2011 2L Diesel, all goes quiet for 7 seconds or so and then the front gives out this loud sigh... like a mini fog horn. Perhaps the front right hand side.

 

I also notice that after a day or so, upon starting the car, the front seems to me to rise for a little longer than before; but I'm not so sure esp as the sigh/foghorn is intermittent.

 

The foghorn problem is my main puzzle. Has this happened to anyone & is there a likely cause that jumps to mind, please?

 

Thanks,

Eddy

[paul.h]

I assume this is an exclusive with hydractive suspension. If you raise the suspension, look to see if the front right suspension strut bellows is a loose fit at the bottom, also check for an oil leak down it (and the other side) which if only very slightly damp is ok but any more and it needs replacing. The thought is an oil leak could be helping to seal the bellows, trapping air until the suspension sinks a bit and builds up pressure and it then blows out. To help locate the noise, stand outside the car, bonnet open and get somebody else to stop the engine.

[Eddyf]

Thank you Paul.  I thought it would have been a bellows type of issue.. It's still under warranty and is going into Citroën tomorrow for a service & check.. I'll mention this to the service guy.  

[coastline taxis]

Have come across this once before 2010 model and it turned out to be the inside of the sphere vibrating

[Eddyf]

Wow.. that would have been tricky to discover..   Thanks for the reply

[coastline taxis]

put your hand on the sphere and get someone to switch the engine off and youl soon no if its the sphere. theres a metal plate inside of the sphere that had come loose ( thats what we thought )  we were going to open it up with a grinder to see but to be honest we just wernt sure wether it retained any pressure when it was off the car so it was left alone and replaced with a new one and no more noise

[Eddyf]

Thank you.  I'm onto it.

[Eddyf]

It was a Turbo electric valve fault.

 

Eddy

[Johndouglas]

BX's often used to make a f**ting noise a short time after being switched off. It was caused by the antiroll bar bushes. An occasional spray with a silicone can kept them quiet.

[Eddyf]

Hi John,

 

Does this mean that, on the C5, the noise audible a short time after being switched off, that's caused by the turbo elector valve, is in turn caused by the antiroll bar bushes? 

 

I'd love to see some pictures if there were any.. 

 

Eddy

[Johndouglas]

I wouldn't think there's any connection between the two noises.   Both the BX and the C5 had different designs of spheres.   The BX has a mechanical suspension pump and the C5 is electric driven.