paul.h

The plastic bit that has broken, Citroen call it a diaphragm and costs a bit under £20. It is a bit of a pig to replace and I did a note on how I did it middle of last year, copied below. It is held on by 3 T20 torx screws and a long (18 inch) screwdriver is needed to reach them, get a few spares at the same time as the part. Edited 26/7/2010 after fitting new screws - 1 was lost and the torx part of 1 was damaged whilst tightening - I would suggest getting a set of new screws before starting, they are only 6p each from Citroen: You need a long T20 torx screwdriver, at least 40 cm to reach the screws. I ended up making one by welding a T20 bit onto a long 10mm rod since using the bit in a socket set all the fittings were too wide so the bit could not reach sideways on to the screw heads. I removed the air filter box cover including the flowmeter leaving them on the fuse box (to avoid undoing the electrical connector), the bellows section, the air filter, the bolt holding the air pipe behind the filter and disconnected (unbolted) the breather pipe at the end of the cam cover and unclipping it from the front support clip - all to give room for access. Stuff a tissue in the gap at the lower edge of the diaphragm fastening plate so loose screws are not lost. With the diaphragm 3 screws removed (and not lost down the back of the engine on to the suspension system) you can reach down the back of the engine with your left hand to pull off the flex pipe whilst holding the part body with your right hand. Fit the flex pipe first to the new diaphragm to help hold it in place. Refitting the left hand screw nearest the engine is not easy - a magnetised torx bit was not much help but holding the screw in a strand of house wire (2.5mm) to position it and then start tightening with the driver, then pull off the wire, worked although still awkward and you still have to locate the driver into the screw head with a finger on the screw. The diaphragm was about £19 from Citroen.

In the calcs it has been assumed the tank was full at the start, 900 miles have been driven and the tank is full now after 900 miles and using about 170 litres giving about 24 mpg. But if it was empty at the start and now full then maybe the answer is hopefully about 50 mpg (about 11 miles per litre). Just to clear it up, Steve, did you start with a full tank, drive south, put in £95 of diesel, drive further and now at 900 miles and then put in 110 euros of diesel and now have a full tank ready for the return. Or is it a petrol car and you have thrashed it ?

Only other things I can think of that may give poor fuel economy are a faulty thermostat so engine runs cold and a temperature sensor fault so causing a rich mixture. There are 2 temp sensors on the C3, both at the end of the cylinder head. The one on top goes to the gauge and the other at the side gives a high temperature alarm. I have assumed it is a manual gearbox. How was the fuel economy on your previous car ?

How many miles has it done, could there be a problem with the exhaust/catalyst blocked up ? Do not know what the symptoms for this would be though. How do you check the mpg, by miles against amount of fuel put in the tank or using the cars computer (if it has one since ours does not) ?

What exactly did it fail the MOT on since driving the car is not really part of the test. Was it a suspension part, tyres not inflated/badly worn/different type on each side, steering part, brakes binding/not balanced, shock absorber fault, etc. Have you recently bumped the car. Could you put the wording from the failure notice on here, it may help with a diagnosis. I would have thought the MOT tester would have told you exactly what was wrong. I do not know about the C2, but on some Citroens the steering assistance is an electric motor and if so there could be a fault with this or its electronics. Haynes do not do a manual for the C2 but if you do not mind using a French dictionary you can get one by ETAI from Amazon's French site or direct from ETAI.

Our 2003 1.4 sx manual usually returns about 45 mpg in summer and about 40 mpg in winter. This December it has been colder than normal so was giving even less. MPG figures from the handbook are 34.4/56.5/45.6 mpg urban/extra urban/combined so you are unlikely to get over 50 mpg and at motorway speeds it is a bit underpowered so maybe not too efficient. Then when you come off the motorway into urban areas the economy drops off.

Another possibility could be a bad earth somewhere such as the battery to body, at the rear of the car, at the side of the front left door pillars. Also do you have a towbar, have you replaced a rear bulb recently, is there a broken wire in the wires at the rear hatch/door hinge area, does the suspension keep going up/down a lot when the car is not in use ? Just thinking of problems that have been reported here before - a good search may bring up something. Other people will hopefully add a bit more help.

What is the battery voltage without the engine running (should be 12.5 to 12.7 volts) ? C5s are known for odd problems when the battery is in need of replacement.

Have you left the suspension pump and all the electronics in place and still fused up (pump maxi fuse no. 8) ? If not, have you written them out of the software or whatever is needed ? Haynes does not show a wiring diagram for the suspension system but there is one in the French RTA (ETAI) manual. This shows that the pump and its electronics are connected to the main BSI system. So as a guess, it could possibly mean it needs the suspension system electronics working for the rest of the car to work. When you unlock the car on the remote the suspension works to set the car at the right height so there must be connections within all the electrics.

The eolys fluid is in a white plastic tank under the car near the fuel tank. A small amount is injected into the fuel tank every time it is filled. It gets a signal from the filler cap which has a magnet in it which is sensed by something in the bodywork near to the filling nozzle. I would think your tank is probably empty unless is has been topped up during servicing. The fluid is supposed to help the soot burn off in the exhaust particle filter so it does not block up. Haynes do a manual for the C5 if you do not have one. Haynes manuals can sometimes be found in libraries.

Door rubbing strip maybe

Haynes C5 manual often mentions Nexia and Proxia as being the ones to use for more than just code reading and Google searches show they may not be that expensive.

Have you checked the fuses in the engine fusebox (including the maxi ones under the top fuse area) and the fuses in the cabin ? What did you do to disable the suspension electronics ? What effect has the mod made to your insurance ?

On the low mpg, I saw a post some time back and a blocked FAP exhaust filter can cause this, so another reason to sort it. In this case it was jet washed out.

Pleased it has worked, and thanks for the excellent posts, should help the rest of us.

Sifaan, looks as if you have another problem with your car when the engine is running (did you get the overheating/leak one sorted) and maybe the WD40 lubrication of the height sensors may fix it. Does the height adjust up/down with the centre switch when the engine is running ? On our C5 2004 2.2 hdi vtr, - unlock the car with remote (doors not opened yet), the pump runs for a short while and car level rises slightly - but if it has been a hot day I have noticed the car height higher than normal before using the remote and in this case when used, the car will sink down slightly. However, if the car battery is not sufficiently charged, on using the remote the pump does not run and the car level does not rise. - open a door and get in the car, the level may sink due to the load but will adjust only once the doors are closed (engine still not running and key not in ignition) - applies also when attaching a trailer to the towbar so usually do this with the doors closed. When the engine is started, the pump is only heard to run occassionally when moving. - lock the car with the remote and car sinks down slightly. - if I get in/out with the engine running the pump is heard to run but I have not noticed the height change whilst I have done this. I have not let a passenger get in/out whilst I have been outside the car with the engine running to see any height change. - with the engine running, the height can be altered up/down using the switch near the handbrake and the pump runs only when raising the car.

It will have a turbo, may be an 8 valve (70 hp) or 16 valve (92 hp) engine though with resulting differences in performance although fuel economy is supposed to be similar. A 1.4 litre diesel engine without a turbo would be underpowered and may need something like a 2 litre non turbo diesel for similar performance.

There is going to be an article on EOBD code readers in the February 2011 issue of Car mechanics, due out 20th Jan. So may help you decide. For about 2 years I have had a Sealey VS863 reader which as well as EOBD code reading also reads/clears Citroen and Renault ABS, airbag and transmission codes. It was a bit expensive but since we have 3 Citroens I thought was probably worth it. It works well, (on 2003 petrol C3, 2004 diesel C5 mark 1, 2008 diesel C4) reads live data as EOBD and can be plugged in to the PC if wanted. Only used it to read/clear one code so far which I had caused by unplugging the C3 engine temp sensor. Since I have not had any ABS or airbag faults, the Citroen part of the reader has not been used to clear anything. The live data bit is useful and has been used to look at indicated high temperature problems on the C3 and I would not buy a reader that can not do this, unless I had a one off code I wanted to clear as cheaply as possible and had no real interest in car maintenance. It did not work on a 1996 7 series petrol BMW with a suitable cable adaptor.

I would check the voltage across your battery, should be 12.7 volts when fully charged, anything less than 12.3 and it is classed as discharged with in between as partially charged. The fact your car starts from jump leads (presumably connected to the battery terminals) indicates the battery is at fault.

'perhaps somebody could confirm this by looking at their V5C' I have not had any response to this but the following on the new C5 may be of interest: In the car handbooks for the new C5 from 1/11/2008 (which can be read and printed by anyone on the service.citroen website as well as other current models) they give the car unladen weight and also the kerb weight which includes the 75 kg for the driver. However, to totally confuse buyers, the sales brochures only give the unladen weight but have called it the kerb weight. Also the handbooks clarify the towing limits for the new C5 and to reach the values in the brochures you have to reduce the payload in the car. In the handbook the nose weight is now called a recommended nose weight yet in the brochure is called max tow hitch download, to add a bit more confusion. e.g. from the handbook 1/11/2009 to 30/6/2010 2 litre 140hp HDI tourer manual - unladen weight 1655 kg, kerb weight 1730 kg - braked trailer 1500 kg - braked trailer (with load transfer within gross train weight limit) 1800 kg - this is the value used in the brochure. - recommended nose weight 72 kg 2 litre 163hp HDI tourer manual - unladen weight 1595 kg, kerb weight 1670 kg - braked trailer 1400 kg - braked trailer (with load transfer within gross train weight limit) 1670 kg - brochure value used. - recommended nose weight 67 kg. This would indicate the 163hp engined car is not as suitable for towing as the 140hp one but also shows the importance of seeing the weights in the handbook before buying rather than just the sales brochure.

If you look on the technical posts, there is a recent one by ataxidriver64 on the subject of removing the filter and remapping the ecu.

Before replacing the sensor, make sure there are no leaks and that all the air has been bled out- these were the causes of similar problems recently reported on a C5 and a Saxo. Also check the wiring and connectors.

Has the oil level increased since you last checked it on the dip stick as opposed to just the dash indication increasing ? If so and you have not put in any more oil, then has the coolant level gone down (and in to the oil via such as a cylinder head gasket failure). If not, then is it a diesel engine ? Our C3 is a manual but when the oil level has shown max, it has not prevented it starting normally so unless the sensodrive is different, then maybe you have another problem.

No, but hopefully coastline (our expert on C5s) may see the post and reply or you could try sending him a note direct.

In the car handbook it says to raise the suspension to its max height before jacking it up - otherwise it will keep trying to level itself/the wheels on the ground may sink/possibly fall off the jack and I seem to remember a post here which caused a lot of suspension problems by not being done (but can not remember what). When raised you should still use axle stands. It appears your exhaust people have done the opposite to what should have been done. When going for tyre changes I always remind the fitters of what should be done and where possible, do it myself before getting out of the car.