A month post replacement my car is going fantastically.
Here are details of replacement of the Swirl Valve Actuator in my 2005 C5.
I've also posted it in the General Fixes category in case anyone searches in future.

This is a detailed description of replacement of the Swirl Valve Actuator on a 2005 2.2 HDI Citroen C5. The engine designation is the DW12TED4. This engine was also fitted to the Peugeot 406 so I assume that they also have this part.

My car had a engine management fault when I bought it and despite spending 8 weeks at 2 different Citroen repairers no-one could fix it. The car would show an ESP/ASR fault followed by an engine management fault and go into limp mode when driven at highway speed despite being normal around town. Once the car was again driven at town speeds and turned off a few times the limp mode stopped and the fault disappeared.
Full details of my journey can be found here including details of the actuator and what it does:

New Citroen C5 Owner

After giving up on the ďexpertsĒ a moderate amount of internet research, mainly on the UK forum where this engine is more common, revealed almost identical faults which were repaired by replacement of the swirl valve actuator.

The new swirl valve actuator (called Diaphragm part number 0363 87 by Citroen) was bought on ebay from the UK for a very reasonable price. I'll call it that from now on.



I noted that a T20 torx driver was required for the 3 screws which hold it on. It is buried deep down in the engine parts and a long driver around 300-400mm is needed to reach it. I couldn't find one locally. There was the option of getting a t20 tip welded on the end of a long driver or buy a short one and get it lengthened but then I found a 300mm on ebay from the UK for just a few pounds.


While I was paying for postage I also bought one of these from the same seller

It's great for removing the top of the fuel filter housing.

Details of replacement are as follows:

To prepare to access the Diaphragm the plastic wind deflector is removed from below the engine. I wont describe this as anyone doing this repair probably already does their own oil changes and would know how to remove it. Once that is removed the 2 hose clamps and 2 retaining bolts are removed from the turbo side air union (0382 R9)which is the plastic pipe that goes under the engine back to front. This will allow you to put your arm up from underneath to access the Diaphragm.

First pull the Diaphragm arm from the Air Intake Butterfly Control Lever (0361 K6)
With a torch the 3 mounting bolts can be visualised from the top. 2 can be removed without disassembling anything but the lower one is in a position where the driver cant be inserted because the oil vapour recycling end pipe (1192 V3) is in the way. To move this the gas recycling tube (1618 55) must be moved. To do this the 2 allen bolts on the front flange are removed then the bolt in the centre that fixes it to it's mount. It can then be moved to the side slightly without disconnecting the back. The single bolt that attaches the oil vapour recycling end pipe can be removed and the part pulled out from the engine to allow direct access to the Diaphragm. The final bolt can now be removed. The small curved vacuum hose can be removed from the Diaphragm from below and the diaphragm removed downward.
I would replace the vacuum pipe as it is often cracked and needs replacing as mine was. I just bought some 4mm ID vacuum hose. The solid vacuum line and all it's other connected lines can be removed from their mounts and carefully pulled upwards from the engine bay in order to replace the small hose as it would be difficult to do from below. They can then be returned to their positions.

The new Diaphragm is replaced from below and held in place while an assistant replaces one or 2 of the bolts to hold it in place. Note that if you drop one of these bolts (6920 A2) as I did it will disappear never to be found. I had to buy a pack of 50 to replace the one I lost (they were cheap) so it anyone needs one or two then PM me.
The new vacuum hose is reconnected and the rest of the screws attached and tightened. The socket end of the diaphragm is clicked onto it's ball then all parts replaced on the order that they were disconnected. The whole job took about 2 hours.

On the first test drive the difference was immediately noticable. There was more power and less turbo lag. It's been over a month now and the fault has never returned.