CX FAQ

Citroën CX Mailing List
Frequently Asked Questions

This FAQ aims to answer some of the common questions that arise on the CX mailing list. Please contact mailto:Alasdair.Mackintosh@eu.citrix.comwith any corrections or comments. Note that certain sections in square brackets [thus] indicate sections that are not complete.

Disclaimer: This information is provided in good faith, in the hope that it will be useful. However, the authors cannot accept responsibility for any inaccuracies or errors, or for any damages that may arise from using this FAQ. If in doubt, please obtain professional advice.

Please read the safety notice in Section 4. NEVER crawl underneath a CX (or any Citroën with hydropneumatic suspension) unless it is properly supported. Do not rely on the suspension pressure to keep the car up. If the pressure falls, the car can descend quickly.

CX Series I Saloon (Sedan)

CX Series II Saloon (Sedan)

CX Series I Familiale (Estate)

1) Buying and running a CX

1.1) What CX models are available?

The CX went through 3 main variants.

"Flat Arch" Series 1. The original CX, launched in 1975. These are now rare in Europe, mainly due to poor rustproofing, and the FAQ will concentrate on the other two variants. (In other markets, e.g. Australia, the early models are more common.)
"Flared Arch" Series 1 - Introduced for the 1982 model year. (Note: a model year actually starts in September, so the 1982 MY runs from 09/81 to 08/82.) These had a slightly wider front track, and flared front wheel arches. Rustproofing was much improved.
Series 2 - 86MY to 89MY. Revised exterior trim (with plastic bumpers) and interiors. New dashboard, more electronics. (Note: The Break continued until 90MY.)

Note that throughout the production period there were various model names, trim options and special accessories, which varied from country to country. It is not practicable to list them all here.

Body Styles

As well as the standard saloon (sedan), there are the following:

Safari:: Estate/Break/Station Wagon version. Enormous carrying capacity.
Familiale:: Seven-seat version of the Safari. Less luggage capacity, as seats cannot be folded down. Note that it is possible to install a Safari interior in a Familiale (or vice versa) as all of the relevant mounting points are there.
Prestige:: Long wheel-base luxury saloon, using Safari floor pan. Well appointed and very spacious. Diesel powered version referred to as "Limousine". Also available as (rare) petrol turbo.

Engine Types

CX2400, CX25, CX GTi Original Citroën Overhead Valve push-rod engine, in 2.4 or (after 1984) 2.5 litre capacity. Very rugged and capable of high mileage. (300,000 miles is not uncommon.) Good performance, but fairly high fuel consumption.
CX2400 has electronic fuel injection, CX25 adds fully electronic ignition. This is the only CX model available with automatic transmission.
(Early models had 2 or 2.2 liter versions of this engine, and some were equipped with a semi-automatic transmission called "C-Matic". This was discontinued in 1981.)
GTi Turbo/Turbo II Turbocharged version of CX25 GTi, with stiffer suspension and anti-roll bars. Turbo II has an intercooler, which improves economy.
CX20, CX22 More modern, all-aluminium Overhead Camshaft engine, also used by Renault, Peugeot and Volvo. (Sometimes referred to as "Douvrin" engine.) Available in 2 or (from MY85) 2.2 litres. Reliable and rugged, if not quite as long lived as the push-rod engines. All Douvrin engined CXs have carburetors, rather than EFI.
Diesel Original diesel has 75 hp, and was fairly slow. Turbo Diesel (TRD in Europe, DTR in UK) was introduced in 1984, with better performance and no loss in economy.

1.2) What are the good and bad points of each model?

In general, there is little difference in terms of quality between the Series I and Series II cars, and the choice is more one of personal preference.

The OHV engines are very rugged, and more powerful than the OHC engines, but have worse fuel economy. The fuel injection & ignition systems are normally reliable, and need no adjustment, but they can suffer from electrical problems. (Although these are nearly always due to poor connections or wiring.)

The turbo diesels are excellent, and command higher resale values, but there can be problems with the engine blocks on the TRD 2. (NOT on the original TRD 1 or Diesel.) The blocks were made of recycled scrap steel, and the impurities in the metal can dissolve, allowing coolant to leak into the cylinders. Only solution is to replace the engine, or reline the cylinders. (Note that any TRD 2 with a reconditioned engine should be OK.) The problem can be avoided by using distilled water and a good quality antifreeze for the coolant. (Do not use tap water, which will help to dissolve the impurities in the block.)

1.3) What should I look for when buying a CX?

Check carefully for rust, especially on the sills, and on the 'chassis' longerons underneath. If a sunroof is fitted, check all around that. Check hydraulic pipes for rust.

The suspension should be very smooth. (See section 3.1 for causes of harsh suspension.) You may want to remove the front wheels to check that the suspension links and balljoint gaiters are OK. When doing this, also check the front disks. (Minimum thickness = 18mm.)

The steering should have a strong self-centering action, even when the car is stationary. There may be an occasional brief loss of power assistance during low-speed maneuvers (e.g. parking) but more serious losses indicate contaminated fluid or other steering problems.

Hold down the rear of the car. After 10 seconds or so, it should rise up again. Let go, and it will rise up. After another 10 seconds or so, it should sink down again. If it takes significantly longer, the height corrector is not working correctly. (Often caused by dirty hydraulic fluid.) Repeat the check with the front.

Check the rear brakes, especially on saloons. (The brake pressure is proportional to the load on the rear suspension, and if there is little load in the rear then the brakes get very little use, and can seize.) With your foot hard on the brake pedal, put the suspension on 'high'. The rear should stay down until you release the brakes, and should then shoot up.

Check that all electrical items work. Check that the heating and ventilation works correctly. (Access to the blower fan and heater matrix is difficult.)

Check for indications of poor maintenance and care.

The LHM in the reservoir should be bright green, not dirty or brown. There should be no leaks of hydraulic fluid anywhere.
With the engine idling and the car stationary at normal height, the hydraulic pump should cut in every 60 to 30 seconds. Lower than this indicates that the main accumulator sphere needs recharging. (If the pump is cutting in very frequently, it may have been damaged by the strain.)
Oil filters are difficult to get at and may not be changed by home servicers.
Cheap tyres are not an encouraging sign

1.4) What fuel consumption can I expect?

Typical figures as reported by list members are:

Engine	Imperial MPG	litres/100km
CX25 (ohv)	20-26	14-11
CX20 (Douvrin)	25-32	11-9
GTI Turbo II	20-30	15-9.5
Turbo Diesel	35-40	8-7

1.5) Can I use unleaded fuel?

All OHV EFI and Douvrin engines can use unleaded. Earlier models are probably safe as well. Sources for this conclusion include:

Unleaded Petrol Info. Manual 3rd Ed. published by Autodata. Describes which vehicles may safely use unleaded. All Citroën CXs (including GTI Turbo) are listed as safe to use with unleaded, without any modifications.
Personal communication from Citroën UK, stating that it is safe to run my 1982 CX2400 on unleaded.
Personal experience of American list-members, who have been running their cars on unleaded for several years now, since leaded petrol is banned in the US.

2) Servicing and Maintenance

2.1) What workshop manuals are availiable? Where can I get them from?

The Haynes manual (ISBN 1 85010 449 2) is recommended, although it only covers the OHV engines. (Not Douvrin or Diesels.) For details, see http://www.haynes.com/If it is not easily availiable locally, try a specialist automotive bookseller, or look at an on-line supplier, e.g. http://groups.yahoo.com/group/CX-L/files/CXFaq/www.chariot.co.uk.

Revue Technique produce a manual (ISBN 2-7268-3955-X) for the CX20/22. (Note that this is in French.)

Revue Technique 96 rue de Paris, 92100 BOULOGNE-BILLANCOURT France

The official factory service manuals are the most detailed. These may still be availiable through Citroën dealers, or through Citroën Andre. (See below.)

2.2) What should I do to a "new" CX?

You might wish to look at the following areas on any newly-acquired CX.

Check/clean electrical plugs and connections. Use vaseline or other waterproof grease.
The oil-pressure sensor on the rear of OHV engines can often leak, and it is sensible to replace it. (Keep the original as a spare.)
Rustproofing with Waxoyl, Tectyl, or a similar oil-based coating is recommended. Spray underneath, paying special attention to hydraulic lines. Spray inside doors (don't block the drainage holes).
Put a thin film of Vaseline around the sun-roof seal, if fitted,

2.3) What tyres should I use?

Note that most CXs have 14x6 inch alloy rims, or 14x5.5 steel. The GTI Turbo, and some Prestige models, have metric rims (390 mm) and a distinctive bead pattern which require special tyres.

Citroën have always recommended Michelin tyres, and these are the "safe" option. Some list members have recommended other tyres:

14 Inch Wheels

(Note: Normal size is 195/75. Some list members have fitted wider 205 or 215 section tyres.)

Michelin. The MVX3a is the current recommended Michelin tyre.
Pirelli P5000s have received good reports from some list members.
Bridgstone Elite 2 have also received good reports.

Metric Wheels

(Note: There are only two known manufacturers of this size of tyre.)

Michelin TRX.
Avon CR28. Cheaper than the Michelins, but wear out more quickly. Opinions divided on whther handling is better or worse than the Michelins.

Putting cheap tyres on a CX is not recommended.

2.4) What hydraulic fluid should I use?

Use LHM fluid, or LHM Plus. Use of other fluids (e.g. Dexron) is not recommended, as they have different characteristics. LHM is easily available in Europe, while in North America and Australia it may also be availiable from Rolls-Royce or Jaguar dealers.) Alternatively, check the suppliers listed below.

2.5) Where can I get spare parts?

Outside North America, all CX parts should be availiable from Citroën dealers, although prices tend to be high. There are numerous independent specialists, including:

Andyspares (U.K.). Large parts supplier, with reasonable prices. Their website features a downloadable parts list. (http://www.andyspares.com/)
Pleiades (U.K.) (+44) 1487 831239. Specialists in Citroën hydraulics. Sells a wide range of components, tools, flushing fluids, etc. Also in Australia (+61) ( 07) 4161-2512.

M&C Lockwood (U.K.) (+44) 1274 621840. General parts supplier. Low prices.
Citroën Andre (Netherlands). Independent Citroën experts. Parts (and cars) shipped worldwide. http://www.citroen-andre.com/
Western Hemispheres (USA) http://www.westernhemispheres.com/

The Citroën Connection website has a list of Citroën parts suppliers (including several in the USA). See
http://www.citroen.mb.ca/netparts/index.html

3) Troubleshooting.

This section describes common CX problems, especially those where the causes are not immediately obvious.

3.1) Poor ride quality

Assuming that tyre pressures are set correctly, and that the car is riding at the correct height, there are two main causes of poor ride quality: low pressure in the suspension spheres, and worn suspension components.

Low sphere pressures will produce firm 'springs' with short suspension travel. A good test for this is to drive over a smooth obstacle such as a speed bump. If the car crashes over the bump, then the spheres need replacing or recharging. If the car drives smoothly over the bumps, but feels harsh when driving over small irregularities in the road, then check the suspension components.

Alternatively, try bouncing each corner of the car in turn. Short, firm travel indicates bad spheres. Any creaking noises suggest suspension wear.

Worn rear bearings may result in the suspension arms failing to align correctly. Check the rear tyres for any sign of uneven wear. Look carefully at the car from behind, and look for any signs that the rear wheels are not vertical. Alternatively, jack up the rear of the car, remove the wheels, put the suspension on 'low' and check for any free play in the suspension arm. Check that the rear anti-roll bar is tightly secured.

To check the front suspension, jack up the front of the car, remove the wheels, and put the suspension on 'low'. Check the balljoint gaiters - any splits mean that grease has leaked out, and the joint may be worn. Check upper and lower suspension arms for any free play at either end, using a long lever. Check anti-roll bar linkages.

3.2) Starting/running problems (Fuel Injection & Electronic Ignition)

Several problems can occur running the EFI engines. They are easily to sort out however.

bad, irregular idling, car seems to run well otherwise: most likely a small leak in the concertina hose between the air flow meter and the inlet manifold. More air is taken in than measured, thus leading to a too poor mixture. A new hose is not expensive.
cutting out of the engine when warm: most likely the / a flywheel sensor has gone bad. When warm, the internal coil opens and no signal can be passed. The ignition and injection computers can no longer calculate their timing and stop. Sensors can be found at the back of the engine (remove spare tire) and can easily be replaced. New ones can be costly though.
A faulty sensor is easily identified in the following way: put the sensor in water (connections above water level) and connect it to a multimeter, measuring its resistance. Now heat the water. The resistance should remain constant with increasing temperature. If resistance increases sharply with temperature the sensor needs replacing.
badly running engine, seems to run on two cylinders only: one of the high voltage coils is shot.
engine does not start. Sparks but no fuel: fuel pump not getting 12 V. Several causes possible:
- flywheel sensor needs replacement (see above)
- connector in feed line loose or corroded. Connector can be found under carpet in RHS front footwell.
- bad connections to the Big Blue relay that can be found behind the RHS headlight. Clean up contacts.

3.3) ABS

Check the wiring connections to the sensors at each wheel, and at the main ABS relays. The wires leading from the sensors can sometimes fracture internally (especially at the front). Check the resistance of these wires while flexing them.

A detailed schematic of the ABS system may be found here.

Alternatively, connect an audio amplifier on to the plug which comes from the sensor (found under the bonnet). With the amplifier in the passenger compartment, connected to the plug via a long screened, or twisted cable, listen to the output whilst you drive down the road. (You may find that the amplifier isn't necessary, and that the signal is strong enough on its own.) Do several right and left turns, drive over humps, listening all the time. You should hear an unbroken tone, varying in pitch in accordance with car speed. Any crackles or sudden break ups suggest that it's the sensor and/or lead.

4) Repairs and Maintenance

Note that the information in this section should be considered as a supplement to a workshop manual, not a replacement. We strongly suggest that you obtain one of the manuals mentioned in section 2.1.

Safety Note:

Working on cars can be dangerous. Please don't undertake any task unless you feel confident in your abilities.

NEVER crawl underneath a CX (or any Citroën with hydropneumatic suspension) unless it is properly supported. Do not rely on the suspension pressure to keep the car up. If the pressure falls, the car can descend quickly.

A CX is best supported with axle stands underneath the four jacking points beneath the sills. (Make sure that there is no rust which could weaken these.) Alternatively, support the car beneath the horizontal tube that runs between and forward of the rear wheels, or beneath the point where the front suspension arms join the subframe. (The two longerons beneath the car, which look like chassis members, should not be used as jacking points.)

When raising one end of the car, it is often easier to put it on 'high', put axle-stands under the relevant jacking points, and then lower the suspension. Don't lower the car while it is supported by the wheel-changing jack, as you can easily twist the mounting points.

Before lowering the suspension, check carefully beneath the car. If one end is supported, make sure that the supports will be secure as the car lowers itself.

Note that the handbrake works on the front wheels. When raising the front of the car, make sure the rear wheels are securely chocked.

Never work on the hydraulic system (including spheres) without de-pressurizing it first.

4.1) Suspension & hydraulics

4.1.1) De-pressurising the hydraulics

Loosen the bleed screw on the pressure regulator by 1 or 2 turns. (Don't unscrew it all the way, or you will lose the small ball-bearing inside.) If the system was under pressure, you will hear a hissing sound.
Note that pressure will remain in the brake accumulator and the piping leading from here to the brake valve. Depreesurizing this part of the hydraulic system needs pressing and depressing the brake pedal several times.

4.1.2) Replacing front suspension bearings & balljoints

Excellent articles on suspension work may be found at:

http://www.fm.uit.no/~knutst/kes/cx/cx.htm
http://hem2.passagen.se/bluestar/workshop.html

4.1.3) Replacing rear suspension bearings

Replacing these bearings is quite straightforward. A few details might need some attention:

bolts keeping the torsion bar attached to the trailing arm may be seized and break. GENTLY undo them. Use lots of grease before refitting.
in case of excessive wear of the bearings the trailing arm may have been damaged, and a replacement arm will have to be installed.

4.1.4) Replacing spheres

Old spheres tend to stick, and a sharp twist is often needed to get them loose. An oil-filter wrench may do the trick - alternatively, Pleiades sell a special tool which clamps around the sphere and allows you to apply the necessary force with a hammer.

When replacing suspension spheres, try to crack them while the system is still pressurized. (This prevents the cylinders from twisting.) Then release all pressure and unscrew the sphere.

After the initial turn, the sphere should unscrew easily by hand. If you need to force it, then the system is still pressurized. Make sure that all pressure is released before continuing, or the sphere will fly out of its housing when it is finally unscrewed.

The rear spheres on a Break/Safari are very awkward. You will need to loosen the clip that holds the cylinder in place, and then slide the cylinder forwards to gain enough clearance.

4.1.5) Replacing hydraulic fluid

Ensure that as much fluid as possible has returned to the reservoir by de-pressurising the system, putting the suspension on low, and pumping the brake pedal several times. Remove the filter block from the tank, and wrap a plastic bag around it to keep it clean. Remove the tank (it may help to syphon out some LHM if it's full). Pour out old fluid, and clean the tank. (The edges of the opening are sharp - watch your fingers.) Remove the filters, and clean them in petrol. (Or in soap and water, and allow them to dry thoroughly.)

If the car fails to rise after refilling the tank, you may need to prime the pump. Unclip the feed hose from the tank and slowly pour in LHM until it overflows. Reconnect the hose.

Bleed the brakes after changing the fluid.

If the old fluid was very dirty, consider flushing out the system with Hydraflush. (Available from Citroën dealers, or Pleiades.) Drain as normal, but refill with Hydraflush. After ~ 1000 miles, drain the flushing fluid and refill with clean LHM.

4.2) Electrics

The physical location of the various components in a Series II car is shown here. The Haynes manual has wiring diagrams for most models.

[Not complete]

4.3) Steering & brakes

4.3.1) Centering the power steering

[I have never done this, so cannot offer advice]

4.3.2) Handbrake adjustment

This is described in the Haynes manual, along with the necessary diagrams. In addition, note the following points:

All linkages in the mechanism must be free.
If the outer sheath on the cables is cracked the cables will need replacing.
Check that the disks are not below the minimum thickness. (18 mm)

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