1965-1972 - 2.2L inline-4 (100-115 hp) with hydropneumatic suspension
The DS is a design and engineering icon - often called "the goddess" - with revolutionary hydropneumatic suspension, power steering, and brakes all running on a single hydraulic system. This complexity is both its charm and its challenge. The 4-cylinder engine is robust and can reach 250,000+ km, but the hydraulic system requires specialist knowledge and regular maintenance. Rust is the primary enemy - it hides in the flat floor pan and chassis boxes. Post-1966 LHM fluid cars are more practical than earlier LHS models. Finding a knowledgeable specialist is essential; without one, ownership becomes difficult.
Flat floor pan and chassis boxes trap moisture and hide corrosion · more· less
Rust is the number one concern with any DS. The platform consists of sheet-metal boxes that trap water and corrode from the inside out. Critical areas include: door frames, sills, footwells, suspension mounts, and where the boot floor joins the rear crossmember. The swing arm attachment points at the rear chassis are particularly vulnerable and nearly invisible until it's too late. If significant rust is found here, the car may not be worth saving. Leaks around the windscreen also let water into the cabin and rot structural components. These cars hide their rot extremely well - professional inspection is essential. Repair cost per wheel arch is approximately €1,000-1,500, but full chassis restoration can exceed €15,000.
Hydraulic system leaks and failures€200 - €3,500
The heart of the DS - powers suspension, brakes, steering, and gearchange · more· less
The hydraulic system is what makes the DS special but also its greatest maintenance challenge. A permanently sagging car indicates a hydraulic fluid leak. The system uses either LHS (red, pre-1967) or LHM (green, post-1966) fluid - these must never be mixed or it will destroy all seals. LHM cars are more practical as LHS fluid is hygroscopic and corrosive. Hydraulic pipes connected to front struts operate at 100+ bar pressure. A leaking pump drips fluid onto the right-hand front brake disc, affecting stopping power. Individual pipe repairs cost €100-200, but a high-pressure pump rebuild costs approximately €350 (exchange). Spheres cost €60-140 each and should be replaced every 5-7 years. Complete system overhaul can reach €3,500.
Suspension sphere failure€300 - €1,000
Gas-filled spheres act as springs - lose pressure over time · more· less
The DS uses gas-filled spheres for each wheel (acting as springs) plus additional spheres for brakes and pressure accumulator. These have internal diaphragms that deteriorate over time, causing the car to ride harshly or sag. A healthy DS may sit slightly higher at the rear, but sagging on one side indicates a problem. Front spheres (LHM, welded type) cost approximately €62 each; screwed type costs €109. Rear spheres are similar. There are two types: rebuildable split spheres and disposable welded ones. A full set of 5-7 spheres plus labor typically costs €500-1,000. Recommended replacement interval: every 80,000-100,000 km or 5-7 years.
The 4-cylinder is generally reliable but cylinder heads can corrode · more· less
The DS engine (1.9L to 2.3L depending on year) is relatively simple and robust, capable of 250,000+ km with proper maintenance. However, cylinder heads can corrode internally - the first warning is often oil contamination of coolant. Engines blowing exhaust smoke are overdue for rebuild. A noisy engine at idle could mean valves needing adjustment (minor) or tired camshafts (major). Oil leaks around the distributor base can indicate camshaft seal failure, which requires separating engine and transmission. Compression should be 120-140 psi per cylinder. A full reconditioned engine costs approximately €7,000 (exchange) from specialists.
Gearbox issues (synchros/bearings)€1,500 - €4,000
Crunching synchros and worn bearings indicated by high-ratio whining · more· less
Manual gearboxes are generally reliable but watch for crunching synchros when shifting and whining at high ratios (indicating worn bearings). Clutch wear can be assessed via an adjustment screw on the bellhousing. The Borg-Warner automatic (if fitted) should be monitored for hesitation between gear changes. Gearbox issues are costly to rectify - ensure the lever easily selects all gears during test drive. The semi-automatic "Citromatic" transmission is particularly complex and best avoided unless you have specialist support.
Steering rack failure€800 - €1,200
Hydraulic power steering rack wears over time · more· less
The DS features hydraulic power steering (DIRAVI on later models) that provides exceptionally light steering at low speeds. The steering rack can wear over time, causing play or leaks. A reconditioned steering rack costs approximately €800-950 on exchange basis. Beware of remanufactured steering at suspiciously low prices. Steering rack gaiters cost €17-20 each and should be inspected for cracks that allow dirt ingress.
Brake system issues€300 - €1,500
Unique inboard front disc brakes powered by hydraulic system · more· less
The DS was the first production car with disc brakes, using inboard-mounted front discs powered by the central hydraulic system. Front brake calipers can stick if the car is parked long-term. Handbrake components are expensive to replace (cables €70-89 each). Rear brakes are more durable and easier to service. Front brake pads cost €60-65 per set; front disc pair costs €85. Brake calipers (LHM) cost approximately €216 each. The brake accumulator sphere costs €249 and is critical for safe braking. Front brake caliper rebuild kit costs €23.
Electrical system problems€200 - €800
French wiring of the era - bad connectors and grounding issues · more· less
French car wiring from this era is known for issues. Common problems include bad connectors that need replacing, incorrect wiring in the wings from previous repairs, and poor grounds. The wiring loom in each wing has its own earth lead - if disconnected or corroded, strange things happen like dim lights or horns blowing when high beams are engaged. Many cars have been partially rewired over the years, so wire colors may not match diagrams. A systematic inspection of all grounds and connectors is recommended.
D-Jetronic electronic injection on later DS21/DS23 can be troublesome · more· less
From 1969, the DS21 was available with Bosch D-Jetronic electronic fuel injection. This system was advanced for its time but is not faultless - the intake air pressure sensor works roughly, and injectors have low impedance without optimal atomization. Symptoms include difficult starting, black smoke, and rough running. Original injectors are no longer available; specialists now fit modern Bosch EV14 injectors with adapters. Carbureted models are simpler to maintain. Reconditioned carburettor costs approximately €400 (exchange).
A rewarding but demanding classic
The DS 21 is one of the most significant cars ever made, but ownership requires commitment. The hydraulic system is ingenious but needs specialist knowledge. Rust is the primary killer - thorough inspection is essential. Join the Citroen Car Club before buying and find a knowledgeable specialist in your area. With proper care, these cars are remarkably reliable and provide an unmatched driving experience.
Pre-Purchase Inspection Checklist
General checks
Service history
Look for records from Citroen specialists. Evidence of regular LHM fluid changes and sphere replacements is particularly important.
Tires
DS uses tube-type wheels - check for correct size (180HR15 or 185HR15 depending on year). Michelin XAS tires are period-correct but expensive (€180 each).
Cold start
After starting, wait for pumps to stop whirring while the car re-levels (about 30 seconds). Listen for any unusual hydraulic sounds.
Body condition
Check for rust, accident damage, paint mismatch. DS panel gaps should be consistent.
Test drive
Minimum 30 minutes including varied speeds. The suspension should be sublime - any harshness indicates sphere issues.
Specific for this vehicle
Check all rust-prone areas thoroughly
Door frames, sills, footwells, suspension mounts, boot floor/rear crossmember junction, swing arm attachment points. Use a magnet to detect filler. Professional inspection strongly recommended.
Verify hydraulic system health
Car should not sag overnight. Check LHM reservoir level and fluid color (should be bright green). Look for leaks around spheres, pump, and all hydraulic lines.
Test suspension leveling
Raise and lower suspension using lever. Car should level quickly and evenly. Sagging on one side indicates sphere or leak issues.
Confirm LHM vs LHS system
Post-1966 LHM (green fluid) cars are much more practical. Pre-1967 LHS (red fluid) systems are corrosive and harder to maintain. Never mix fluids.
Check engine compression
Should be 120-140 psi per cylinder. Oil in coolant indicates head gasket or cylinder head corrosion. Exhaust smoke means overdue rebuild.
Test all gears thoroughly
Feel for crunching synchros, listen for whining at high ratios. Check clutch adjustment screw on bellhousing.
Inspect brake operation
Brakes should be progressive and powerful. Check for hydraulic leaks around inboard front brake calipers. Test handbrake effectiveness.
Examine electrical system
Test all lights, horn, wipers. Check grounds in both front wings. Look for evidence of rewiring.
Recalls and Technical Service Bulletins
No outstanding recallsVehicle age exceeds recall programs
Due to the age of this vehicle (50+ years), no manufacturer recalls are active. Focus instead on verifying maintenance history and having a specialist inspect the hydraulic system, chassis integrity, and engine condition. Join the Citroen Car Club for technical support and access to specialists who know these cars.
Warranty Status
Factory warrantyNot applicable (classic car)
Classic car insuranceAgreed value policies available
Parts availabilityGood from specialists
As a classic car, standard warranties do not apply. However, parts availability is surprisingly good through specialists like CIT'art Europe, Franzose, and Citroen Classics. Many mechanical parts are still manufactured new. Agreed-value classic car insurance from specialists like Adrian Flux offers coverage tailored to classics with limited mileage discounts.
This report is for informational purposes only and does not constitute professional advice. Estimates may be inaccurate. Always have a qualified specialist inspect the vehicle before purchase. We accept no liability for decisions made based on this information.