Whenever I come here all I see are C5 questions. Are they terrible, popular, or both?!

[kenbw2]

From what I see here, noone should touch them with a barge pole!

[GiveMeABreak]

I think it's fair to say that previous vehicles like the Xantia had their fair share of questions back in the day - just look at all the posts, but like everything, people move on and the same with the move to newer / replacement vehicles. The C5 MK I and II spanned a good 7 years of production until the MK III which on its own achieved a further 8 years. So these are more current and the last ever Hydraulically suspended Citroens to be produced.

Yes, they are more complex as they house a lot of electronics with less 'spannering' involved nowadays, but they are obviously quite popular - I am of course biased as I own one

[kenbw2]

I had a feeling they're just popular, especially with people who want to have a go with things themselves. Just even knowing that, thought they were quite well represented on the forum.

Maybe they are that popular though

[daviemck2006]

When I joined this forum years ago when I had a problem with a c5, there were very few c5 on here I used to joke it was a xantia forum! Most of those xantia owners now have a c5, Ive went the opposite way, had a c5 now have a xantia!

[Homer]

Over the years I've seen people make the same comment about the BX and Xantia.

It's not that these cars were problematic, it's that they were unusual. If you have a boring generic Pug or Renault, then you have a million and one places you can go for advice, no need to come to a specialist forum.

The C5 X7 though, that's one I'd stay away from.

[Stickyfinger]

I have had all of the C5's, a few aspects of them need some care but no more than most makers cars.
C5x7 is the best ever, most reliable and certainly most capable Citroen made IMHO

[white exec]

Electrical wiring BX onwards has always been pretty copious and complex, but the move from the CX/BX era to XM and Xantia saw the beginnings of multiple ECUs to control several functions.

Xantia was highly successful on the back of previous transformational BX sales (especially in the UK), and I reckon a good many owners took Xantia on not fully appreciating the intensely clever workings of Hydractive. When new, Xantia (and XM) just worked - like most new cars - and significant issues were likely mopped up by warranty.

Those of us 'into' the detailed workings of Citroen hydropneumatics and Hydractive - an intellectual challenge in itself - got our brain cells around how most of it worked, but only had to cope with essentially simple electro-mechanical units and very basic electronics, with the exception of the main engine (injection) and suspension ECUs. These last units have proved extremely robust in the main, and so little need to delve inside them. (Even failures of VN05N's are rare.)

So, given a reasonable familiarity with fluid suspension and/or Hydractive, and the ability to chase some wiring and voltages around, DIY fault-finding and fixing was something not too difficult to do, even without Lexia. Well, that was Xantia and XM, of a similar generation.

The evolution of C5 brought whole new levels of complexity and electronic control, making access to Lexia almost obligatory. The move away from mechanically-powered components and replacement with electrical ones has certainly meant a change in the tool kit, and may well have been driven by a desire to
- reduce manufacturing costs and tolerances
- shave a whisker off fuel consumption figures
- allow fine control and interactive control of devices
- improve reliability
- maximise the need for specialist (dealer) workshop repairs
- change the recycling requirements for a vehicle being scrapped.
Some of these motivations could well be questionable.

As C5 evolved, it became an extremely attractive vehicle, but electrical/electronic complexity multiplied. As it did so, so did the demands on the electrical system (we're now seeing alternators of 180amp+), to the point where designers have had to come up with ways to make sure this load doesn't fall too heavily on the engine - especially the smaller ones - and threaten quoted mpg figures. The traditional 12v system we're still lumbered with doesn't help with these high-wattage devices, and cabling, connections, fuses and batteries are now very much working at their installed limits.

Realistically, though, none of this will go away. The welcome progress towards all-electric transport will actually accelerate it - and certainly severely dent an owner's ability to work on, let alone understand, what's there, how it works, and how to fix things. OK, so that is already true of most of us and our domestic gadgets, especially LCD tv's, and most folk are happy with that.

What it might mean, though, is that the attractions of classic cars - with their inherent ability to be readily understood and fixed - could well be assured. Whether X7 fits in there, I'm not sure. My guess is, it will - for a select few. Bit like XM, really . . .

[JohnD]

When I joined the forum it seemed to be the place to go to get answers for BX problems. In fact I was looking for help with my leaking octupus. At the time Bob Smith was the guy with all the know-how. I took his advice and bought a replacement. I spent the next several days replacing all the pipework. Four years later Bob bought the BX from me. He kept it for years before disappearing from the forum.

[Peter.N.]

I ran hydropneumatic Citroens for about 30 years from the CX to the C5 and I must admit I wasn't overly impressed with the C5. Apart from not riding as well as the early ones they don't seem to be as reliable, well mine certainly didn't. I have been running 406 Hdi's for the last 8 or 9 years and although they have the same running gear as the C5 apart of course for the hydraulics, which rarely gave trouble, I had a lot of problems with my last one but the 406's seem to be bombproof as well as a nice car to drive, trouble is there aren't many about now.

Peter

[Paul-R]

When I joined the forum in 2006 after buying my Mk1 C5 there wasn't a huge amount of chatter about C5s. As the years went by that increased and Xantia talk decreased.

While I still had the Mk1 I noticed that the X7 started appearing in posts and by the time I bought my own it was about 50/50 Mk1/2 and X7. Nowadays there are more X7s and consequently more X7 chatter.

And then, if you look at it with an outsider's eye, if you lump all the C5 variants in together you're bound to see a preponderance of talk about C5s.

Simples.

[GiveMeABreak]

The evolution of C5 brought whole new levels of complexity and electronic control, making access to Lexia almost obligatory. The move away from mechanically-powered components and replacement with electrical ones has certainly meant a change in the tool kit, and may well have been driven by a desire to
- reduce manufacturing costs and tolerances
- shave a whisker off fuel consumption figures
- allow fine control and interactive control of devices
- improve reliability
- maximise the need for specialist (dealer) workshop repairs
- change the recycling requirements for a vehicle being scrapped.
Some of these motivations could well be questionable.

As C5 evolved, it became an extremely attractive vehicle, but electrical/electronic complexity multiplied. As it did so, so did the demands on the electrical system (we're now seeing alternators of 180amp+), to the point where designers have had to come up with ways to make sure this load doesn't fall too heavily on the engine - especially the smaller ones - and threaten quoted mpg figures. The traditional 12v system we're still lumbered with doesn't help with these high-wattage devices, and cabling, connections, fuses and batteries are now very much working at their installed limits.

There's also one other significant thing we meed to factor in here and that is the European standards and legislation (for the moment anyway - but I can't see that changing regardless).

As manufacturers are being told they must cut emissions and must improve safety and everything must be recyclable etc. this inevitably leaves design challenges in order to comply with certification for cars made /sold / used in European countries. I think it's worth an example here of comparing the very reliable DW10BTED4 2.0 HDi 138 engine (and specifically in the following comparison as used in the early C5 X7s) against the in-year modifications that came in, resulting in the DW10CTED4 engine 2.0 HDi 163 in 2010. Here are some of the modifications that were made for a variety of the aforementioned reasons:

New Preheater Plugs	Air flow meter
Metallic and ceramic low-voltage preheat plugs to withstand the increased engine temperature and the low compression ratio linked to a more rapid preheating (Complying with emission control standard Euro 5)	Modification of the air flow sensor for a lifespan of 160 000 km.(Complying with emission control standard Euro 5)
Air Metering Valve	Air Filter
Pneumatic double air mixer. (Double inlet air doser unit.)	Increased air flow rate.
Fuel Filter Location	Piloting Electrovalves
New location of the diesel fuel filter to comply with high speed impact. Euro Safety	The integral vacuum reserve is linked directly with the control electrovalves.
New Injection Circuit	Vacuum Circuit
The pressure in the fuel high pressure injection circuit is kept at 2000 bars in order to improve the time taken for the temperature to rise and to favour the starting capacity. The DW10BTED4 engine pressure in the fuel high pressure injection circuit was 1600 Bars.) The fuel low pressure injection circuit has the diesel fuel temperature sensor as well as double locking of the connectors.	Modification of the vacuum pump and the vacuum circuit to meet the following new constraints: Burden on the braking system (increase in engine weight) Separation of the braking and the engine vacuum circuit Increased burdens on the actuators (Regulated electrovalves controlling the variable geometry turbocharger - Control electrovalve for the EGR heat exchanger by-pass - Regulated electrovalves controlling the double mixer)
Exhaust	RH Engine Support
New exhaust line (Complying with emission control standard Euro 5).	This modification relates to the increased engine weight and torque (8,7 kg extra relative to the DW10BTED4 engine).
Cooling Front Panel	Engine Fuse Box - (In the engine compartment Front left section)
Application of the Euro 5 Emission Control Standard Entails an increase in the temperature under the bonnet, resulting in the fitting of a "sucking" type cooling fan in place of a "blowing" type cooling fan (Standard Euro 4). To increase the flow of cooling air, the "sucking" type cooling fans are positioned to the rear of the following front panel components: Cooling radiator Air conditioning condenser Turbocharging Air Cooler New anti-recycling bulkheads[/list	Complying with emission control standard Euro 5 Increased volume for the new engine fusebox, relating to the location of the new engine ECU. Note: Discontinuation of the air flow duct for cooling the engine fusebox type EURO 4.
New Engine Fusebox	New Engine Management ECU
(Complying with emission control standard Euro 5).	(Complying with emission control standard Euro 5).
Front Suspension	New Subframe
Modification concerning the front suspension relating to the increase in engine weight and torque.	New front subframe in steel with rectilinear crossmember (discontinuation of the crossover) to allow the exhaust line to pass above the flat section of the front subframe (Except C5 China).
Torque Reaction Rod	Bodywork
Complying with emission control standard Euro 5:The torque reaction rod between the front subframe and the engine, on the rear right section, is in the horizontal position. Note: Under Euro norm 4, the Torque Reaction Rod was in the vertical position.	Modifications relating to the new European high speed impact standards New attachment system for the cable on the bonnet release lock. Modification of the cut-out for the front bumper panel and for the routing of the cable guide.

So the more they have to shave off emissions, reduce weight, use less fuel (oh and save money to recuperate all the costs) to comply with all the legislation, the more re-engineering and control technology they have to employ to make it all work. The increase in sensors and control units to make everything work will surely result in additional component failures. That has to be the price of 'progress' I guess.

Although it will financial and economic sense to employ these same engines across a range of the vehicles, one does wonder how the C5 'China' edition compares and whether they have produced a vehicle with less stringent constraints - of which the same engine can be used in other PSA vehicles for that particular market....

[Paul-R]

New location of the diesel fuel filter to comply with high speed impact. Euro Safety

So that's why it's such a b@stard to get to!

[GiveMeABreak]

Exactly - when it comes to complying with regs and available space in the engine bay - there is little regard for the DIY mechanic It'll just add another hour or two to the dealer labour time to do it no doubt!

[white exec]

A common thread running through many of those modifications is increased weight, and increased operating temperature - which sits very uncomfortably with notions of potential efficiency.

OK, today's turbo-diesel, in particular, is an impressively powerful thing - but it is being obliged to almost collapse under its own weight and complexity, and to run on (and clog up on) its own exhaust. Recent photos here of EGR and inlet manifolds show them to be far dirtier and clagged up than the car's own exhaust pipe! I suppose it's one way of getting ICE vehicles to put less grot out of the exhaust: oblige it to accumulate 'on board' - but in the inlet manifold? What t*at thought that up - just to get oxygen intake down?

It's all a bit academic now, and time to call it a day for these millions of engines dirtily and expensively moving along our urban streets. Some justification (for a while) for inter-city freight, but not for the local commute. Energy generation needs to be done centrally, cleanly and efficiently; thousands of individual cars throwing out untold quantities of heat and fume no longer makes sense.

Meantime, am I alone in finding the extraordinary complexity of new cars just plain embarrassing, and, incidentally, a near-impossible challenge for owner-enthusiast maintenance? (The trade doesn't get universally excited about it either.) Most modern technologies strive and manage to achieve more with less - take the DVD recorder/player, for example, where current models have "virtually nothing" inside them, and sell for 30 bucks. The ICE car, on the other hand, is literally dying under the weight of its add-ons. Well, we all have to go somehow.

Marc, thank you for tabulating all that information. It really does illustrate the crazy lengths to which engine designers are continually obliged to go, to keep their plants in business. At some point, though, it surely makes sense to stop flogging the dead horse, and start afresh.

[GiveMeABreak]

Couldn't agree more Chris - all geared to getting the car up to operating temp as soon as possible to reduce emissions! More tech required to do this, more weight thus increase engine power... As for the engineering side now - little to no repairs undertaken on anything at the main dealer now - they won't even fix a snapped electric window regulator wire - no, the whole unit including motor were all replaced on mine! Same with height correctors - although no a lot you can do with these, just throw away and replace & re-programme. Same with the BSI and engine fuse boxes, non repairable they will say, just replace and programme - although we know Mike recently has successfully replaced a C3 relay in the BSI.