The Citroën SM, produced from 1970 to 1975, was one of the most technically ambitious grand touring cars of its era. Combining Citroën’s advanced hydropneumatic suspension, front-wheel drive and distinctive aerodynamic styling with a Maserati-designed V6 engine, the SM offered an extraordinary blend of performance, comfort and engineering innovation. Few production automobiles of the early 1970s incorporated so many unconventional technologies in a single package.
The SM emerged from Citroën’s acquisition of Maserati in 1968 and was conceived as a high-performance flagship positioned above the DS. Its sleek two-door body, self-leveling suspension, speed-sensitive power steering and sophisticated braking system distinguished it from conventional European grand tourers.
Production totaled approximately 12,920 cars, making the SM relatively rare. Although most were built as standard two-door coupes, the model also spawned several important variations, including carbureted and fuel-injected versions, different engine displacements, automatic-transmission models and exceptionally rare coachbuilt derivatives such as the Chapron Mylord convertible and Opéra four-door sedan.
Today, the SM is valued for its remarkable engineering, distinctive styling and unusual combination of French and Italian automotive traditions. Its complexity requires specialist maintenance, but a properly sorted example delivers a driving experience unlike almost any other classic grand tourer.
Origins: Citroën Meets Maserati
During the 1960s, Citroën explored the possibility of developing a high-performance grand tourer using technology derived from the DS. The project, initially known internally as Project S, sought to combine Citroën’s advanced chassis engineering with substantially greater performance.
Citroën’s acquisition of Maserati in 1968 provided access to the Italian manufacturer’s engine-development expertise. Maserati engineer Giulio Alfieri was tasked with creating a compact V6 suitable for installation in a front-wheel-drive Citroën.
The resulting engine was developed rapidly, using a 90-degree V6 configuration that allowed it to fit within the SM’s relatively low and narrow engine compartment.
The SM debuted at the 1970 Geneva Motor Show and entered production later that year. Its name is generally associated with Citroën’s Project S and Maserati, although the precise origin has been interpreted in different ways.
The car represented Citroën’s attempt to compete with prestigious European grand tourers while retaining the company’s unconventional approach to engineering.
Robert Opron’s Aerodynamic Design
The SM’s dramatic styling was developed under Robert Opron, Citroën’s head of design.
Its long, low body featured a sharply tapered nose, flowing roofline, enclosed rear wheels and a broad glass-covered front lighting assembly. The shape emphasized aerodynamic efficiency and high-speed stability rather than conventional sports-car proportions.
European-market cars featured six headlights behind a transparent front panel, with the inner lamps turning in conjunction with the steering. The lighting system was integrated with the car’s hydraulic technology, helping maintain correct beam alignment.
The SM’s distinctive rear bodywork incorporated a large glass hatch, making it more practical than its coupe appearance suggested.
Aerodynamic development contributed to a drag coefficient commonly quoted at approximately 0.26, an exceptionally low figure for a production car of the period, although published measurements vary.
The design remains one of the most recognizable expressions of Citroën’s futuristic styling philosophy.
The Maserati V6 Engine
The SM used a compact, all-aluminum 90-degree V6 developed by Maserati under Giulio Alfieri.
The original engine displaced 2,670cc and featured dual overhead camshafts for each cylinder bank. Its unusual 90-degree configuration contributed to compact packaging but required careful engineering to achieve acceptable smoothness. Early European models used three Weber twin-choke carburetors and produced approximately 170 DIN horsepower.
For 1972, Citroën introduced Bosch D-Jetronic electronic fuel injection, increasing output to approximately 178 DIN horsepower in European specification. A larger 2,965cc V6 was also introduced, primarily for automatic-transmission models and certain export markets. Output varied according to carburetion, emissions equipment and market requirements.
The Maserati V6 provided smooth, high-speed performance and a distinctive exhaust note, but its specialized construction also contributed to the SM’s reputation for demanding maintenance.
1970 Citroën SM coupe, from an auction at Amelia Island on March 8th, 2018
The Original SM 2.7 Carburetor: 1970–72
The earliest SMs used the 2.7-liter carbureted V6, paired with a five-speed manual transmission.
With approximately 170 DIN horsepower, the original SM offered performance comparable to many contemporary European grand tourers. Its engine used three Weber carburetors, providing responsive power delivery when correctly adjusted. However, synchronization and tuning required specialist knowledge.
Early cars incorporated distinctive interior details, dashboard equipment and trim that evolved during production.
These first-generation SMs are particularly appealing to collectors who value the original specification and the mechanical character of the carbureted engine.
1972 Citroën SM coupe, from an auction in Scottsdale on January 27th, 2022
The SM 2.7 Injection: 1972–75
The SM Injection, introduced in 1972, replaced the carburetors with Bosch D-Jetronic electronic fuel injection. The fuel-injected engine produced approximately 178 DIN horsepower in European specification and offered improved fuel metering and drivability. The system used electronic sensors to determine fuel delivery, representing a significant technological advance over conventional carburetors. However, the injection system introduced additional electrical components and wiring that can deteriorate with age.
Fuel-injected SMs are attractive to enthusiasts seeking the most developed version of the original 2.7-liter engine, although proper diagnosis and maintenance require familiarity with Bosch D-Jetronic systems.
1972 Citroën SM Automatic, from an auction on April 24th, 2026
The SM 3.0 Automatic
The 3.0-liter SM used a larger 2,965cc version of the Maserati V6, generally paired with a Borg-Warner three-speed automatic transmission. The larger engine was introduced partly to compensate for the automatic transmission’s power losses and provide stronger low-speed torque. In European specification, the 3.0-liter carbureted engine produced approximately 180 DIN horsepower, although U.S.-market ratings were lower under contemporary SAE net measurement standards.
The automatic SM offered a more relaxed grand-touring character than the five-speed manual versions. Its combination of increased displacement and automatic transmission made it particularly suitable for American buyers, where automatic transmissions were widely preferred.
Today, the 3.0 automatic appeals to collectors who value smooth cruising and effortless operation, although manual-transmission examples generally attract greater enthusiast interest.
1973 Citroën SM coupe – US version, from an auction in Arizona on January 16th, 2020
U.S.-Market Citroën SM
The SM was officially sold in the United States from the early 1970s, with approximately 2,400 examples imported. American-market cars differed from European versions in several important respects. U.S. regulations prohibited the European glass-covered, swiveling headlight arrangement, so American cars used exposed fixed headlights with a different front-end treatment.
Federal emissions requirements also affected engine tuning and equipment. American cars were offered with both manual and automatic transmissions, and later examples used the larger 3.0-liter V6. The SM received considerable attention from the American automotive press and was named Motor Trend’s 1972 Car of the Year, an unusual achievement for an imported luxury automobile.
However, changing safety regulations, emissions requirements and Citroën’s financial difficulties contributed to the end of U.S. sales.
The Five-Speed Manual Transmission
The SM’s five-speed manual gearbox was mounted ahead of the longitudinally positioned engine, reflecting the car’s unusual front-wheel-drive layout. The transmission provided relatively close ratios suited to the V6’s high-revving characteristics. The manual SM was capable of impressive high-speed cruising, with the engine operating smoothly at sustained motorway speeds. Gear selection was generally precise when the linkage and synchronizers were in good condition.
Manual-transmission examples are often preferred by collectors because they provide a more engaging driving experience and better exploit the Maserati engine’s character.
Hydropneumatic Suspension
The SM inherited Citroën’s celebrated hydropneumatic suspension system, originally developed for the DS. The system used hydraulic fluid and pressurized nitrogen spheres to provide springing and damping, automatically maintaining ride height regardless of passenger or luggage load. The SM could raise or lower its suspension to accommodate different road conditions, while the system maintained a remarkably smooth ride over uneven surfaces.
Unlike conventional steel springs, the hydropneumatic system provided a distinctive combination of comfort and controlled body movement. The suspension also contributed to the SM’s exceptional high-speed stability, allowing the car to remain composed over rough roads at speeds that challenged many contemporary grand tourers.
Although sophisticated, the system can be reliable when properly maintained with correct hydraulic fluid and components.
DIRAVI Speed-Sensitive Steering
One of the SM’s most remarkable features was its DIRAVI power-steering system, short for Direction à Rappel Asservi. Unlike conventional power steering, DIRAVI used hydraulic pressure to control steering assistance and provide automatic self-centering.
Steering effort increased with vehicle speed, making the system extremely light during parking maneuvers while providing greater resistance at high speeds. The steering also returned toward center automatically, even when the car was stationary. Its unusually quick response and strong self-centering action required drivers to adapt, but the system provided exceptional precision once familiar.
DIRAVI became one of the SM’s defining engineering achievements and was subsequently used in other Citroën models.
Hydraulic Braking System
The SM used a high-pressure hydraulic braking system integrated with the car’s central hydraulic architecture. Rather than a conventional brake pedal, the driver operated a small, pressure-sensitive control often described as a brake button. Only minimal pedal travel was required, with braking force determined primarily by pressure applied to the control.
The system provided powerful braking with relatively little physical effort, but its sensitivity could surprise drivers accustomed to conventional brakes. Four-wheel disc brakes were standard, with the front discs mounted inboard near the transmission to reduce unsprung weight.
Proper maintenance of the hydraulic system is essential because suspension, steering and braking functions depend upon reliable hydraulic pressure.
Performance and High-Speed Touring
The SM was designed primarily for sustained high-speed travel rather than aggressive acceleration.
European 2.7-liter manual models were capable of approximately 220 km/h (137 mph), while acceleration from 0–100 km/h generally took around nine seconds, depending upon specification.
The car’s aerodynamic body, long wheelbase and self-leveling suspension provided exceptional stability at motorway speeds. Its front-wheel-drive layout offered predictable traction, while DIRAVI steering delivered unusually precise directional control. The SM’s greatest strength was its ability to cover long distances quickly and comfortably, particularly on the high-speed European roads for which it was designed.
1975 Citroen SM Chapron le Paris cabriolet, from the Chantilly Concours in 2015
The Chapron SM Mylord Convertible
One of the rarest and most desirable SM derivatives was the Mylord convertible, created by French coachbuilder Henri Chapron. Introduced in 1971, the Mylord transformed the SM coupe into an elegant open-top grand tourer. The conversion required extensive structural reinforcement and redesigned rear bodywork to accommodate the folding convertible roof.
Chapron retained the SM’s distinctive front-end styling and Maserati V6 drivetrain while creating a more exclusive body configuration. Only seven Mylord convertibles were completed, making them exceptionally rare.
Today, genuine Mylords occupy a separate collector category from standard SM coupes, with authenticity and coachbuilder documentation of paramount importance.
The Chapron SM Opéra Sedan
The SM Opéra was another remarkable coachbuilt derivative created by Henri Chapron. Introduced in 1972, the Opéra transformed the two-door SM into a luxurious four-door sedan. The wheelbase was extended, and the body was substantially redesigned to accommodate rear doors and a more spacious passenger compartment.
Despite its increased length, the Opéra retained the SM’s distinctive aerodynamic character and advanced mechanical systems.
Only eight examples were built, making it one of the rarest Citroën production-based automobiles. The Opéra appealed to buyers seeking an exclusive luxury sedan with the SM’s advanced technology and Maserati engine.
The SM Présidentielle
Chapron also created two special SM Présidentielle convertibles for the French government in 1972. These long-wheelbase, four-door open cars were intended for official ceremonial use, including state visits and presidential processions. Their bodies were extensively modified, with elongated passenger compartments, special interior arrangements and folding roofs.
The Présidentielle cars retained the SM’s basic mechanical architecture but were designed for low-speed ceremonial operation rather than high-performance touring. Only two examples were constructed, and they remain among the most historically significant SM derivatives.
The Citroën SM in Competition
Although the SM was primarily a luxury grand tourer, Citroën also explored its potential in rallying and endurance competition. The model achieved a notable victory in the 1971 Rallye du Maroc, demonstrating the durability of its suspension and drivetrain under demanding conditions.
Competition SMs incorporated modifications to suspension, bodywork and mechanical equipment to withstand rough terrain and extended high-speed operation. The SM’s front-wheel-drive layout and sophisticated suspension provided advantages on uneven surfaces, although its size and mechanical complexity limited its broader competition potential.
Factory-supported rally cars and documented competition examples are historically important, but they were produced in extremely small numbers.
The SM Breadvan and Special Competition Bodies
One of the most unusual SM derivatives was the SM Breadvan, developed by French specialist Regembeau and other competition-oriented builders.
These cars incorporated dramatically modified bodywork, often featuring extended or squared-off rear sections intended to improve aerodynamics or accommodate specialized equipment. Some competition-oriented SMs also received enlarged engines, revised induction systems and modified suspension. These vehicles were not regular factory-production models, and their specifications varied considerably.
Collectors should distinguish genuine period competition cars from later custom conversions or replicas.
Why SM Production Ended
The SM’s production life was cut short by a combination of economic and corporate difficulties. The 1973 oil crisis reduced demand for large, relatively thirsty grand tourers, particularly those with expensive and complex mechanical systems. Citroën was also facing serious financial problems, partly associated with ambitious development programs and the costs of operating Maserati.
In 1974, Peugeot acquired a controlling interest in Citroën, leading to a reassessment of the company’s model range. The SM was considered too expensive and specialized to justify continued production. Manufacturing ended in 1975, after approximately 12,920 cars had been built.
The SM’s short production run contributed to its rarity and eventual collector appeal.
Engine Timing-Chain Problems
The Maserati V6’s timing-chain system is one of the most important maintenance concerns. The original engine design used a complex arrangement of chains, guides and tensioners, and deterioration can lead to serious engine damage. Early engines were particularly vulnerable to timing-chain tensioner problems, making inspection and appropriate upgrades essential.
Specialists have developed improved tensioners and related components to address weaknesses in the original design.
A prospective buyer should verify whether the engine has received appropriate timing-system updates and whether maintenance has been performed by an experienced SM specialist.
Exhaust Valves and Engine Reliability
The SM’s V6 can also suffer from problems involving exhaust valves, particularly when engines have been operated at high temperatures or maintained improperly. Original valve materials and certain engine components have been associated with durability concerns. Modern replacement valves and improved components are available from specialist suppliers.
Cooling-system condition, ignition timing and carburetor or fuel-injection calibration are particularly important because overheating or incorrect tuning can accelerate engine wear.
A properly rebuilt and maintained SM engine can be reliable, but deferred maintenance can lead to extremely expensive repairs.
Hydraulic-System Maintenance
The SM’s hydraulic system controls suspension, steering and braking, making it central to the car’s operation. Common problems include deteriorated hydraulic hoses, leaking seals, worn pumps and aging suspension spheres. The system must use the correct hydraulic fluid. Most production SMs use LHM mineral hydraulic fluid, and incompatible fluids can damage seals and components.
A healthy system should raise the car smoothly, maintain correct ride height and provide consistent steering and braking assistance. Leaks or pressure problems should be investigated immediately because failures can affect multiple vehicle systems.
Although the hydraulics appear intimidating, experienced Citroën specialists generally regard them as manageable when maintained correctly.
Body Corrosion and Restoration
The SM’s steel body is vulnerable to corrosion, particularly in areas where moisture can accumulate. Common rust locations include the floor pans, rocker panels, wheel arches, door bottoms, rear body structure and suspension mounting areas.
The car’s complex body shape and limited production make replacement panels difficult to source. The distinctive front lighting assembly and glass-covered European nose are particularly expensive to restore or replace. Interior trim, stainless-steel details and specialized exterior fittings can also be difficult to obtain.
A structurally sound SM with complete original trim is generally a much better restoration candidate than a heavily corroded or incomplete example.
Electrical and Fuel-System Problems
The SM’s electrical system is relatively sophisticated for a car of its era and can suffer from age-related wiring and connector problems.
Fuel-injected models require careful attention to Bosch D-Jetronic sensors, wiring and fuel-pressure regulation. Carbureted cars may experience problems caused by worn throttle linkages, vacuum leaks or incorrect carburetor adjustment.
The retractable and swiveling headlight mechanisms on European cars also require maintenance.
Because many systems are interconnected, diagnosis should be performed methodically rather than by replacing components at random.
Understanding the Major Citroën SM Variants
- SM 2.7 Carburetor (1970–72): Original 2,670cc V6 with three Weber carburetors and five-speed manual transmission.
- SM 2.7 Injection (1972–75): Fuel-injected 2.7-liter version using Bosch D-Jetronic electronic fuel injection.
- SM 3.0 Automatic (1972–75): Larger 2,965cc V6 paired with a Borg-Warner three-speed automatic transmission.
- U.S.-Market SM (1971–73): Federalized specification with exposed fixed headlights and market-specific emissions equipment.
- Chapron SM Mylord (1971–74): Extremely rare coachbuilt convertible, with seven examples completed.
- Chapron SM Opéra (1972–74): Four-door luxury sedan conversion, with eight examples built.
- SM Présidentielle (1972): Two long-wheelbase ceremonial convertibles built for the French government.
- SM Competition and Rally Cars: Factory-supported and privately modified competition examples, including cars associated with the Rallye du Maroc.
- Specialist-Modified SMs: Cars incorporating later engine upgrades, performance modifications or custom bodywork.
Important Sales Reviewed by SCM Experts
In each month’s issue for the past 38 years, SCM’s analysts have reviewed 5 to 7 significant cars sold at auction, and discuss what options, history, or details made that particular more or less valuable. They give their expert opinion on the market for these cars, and whether this car was well bought or well sold. If you’re thinking of purchasing a Citroën SM, you’ll likely find these profiles critical in helping you make the right decision. Each of the following is an article from our print magazine on a Citroën SM sold at auction.
1974 Citroën SM CoupeCombining Citröen’s advanced chassis technology and Maserati’s unrivaled engine know-how, the SM (Série Maserati) featured DS-style hydro-pneumatic self-leveling suspension; power-assisted all-around disc brakes; self-centering steering; and steered headlamps. Maserati was responsible for the 90-degree V6 engine, and after some juggling of bore/stroke dimensions, a capacity of 2,670 cc was settled on for a power output […]Read more
1971 Citroën SM CoupeWhat makes this Citroën SM special is that it is as close to a new car as is possible to be following a no-expense-spared restoration. It was given to the renowned Garage du Lac, run by Vincent Crescia in Switzerland, for a total mechanical and body rebuild. New or refurbished parts were fitted throughout, and […]Read more
Cars For Sale
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Books on the Citroën SM
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Past Auction Sales – Citroën SM
Average Citroën SM Sale Price by Year from SCM’s Platinum Auction Database:
Includes sales listed as Citroën SM Coupe.
Citroën SM Sales from SCM’s Platinum Auction Database:
Kruse Auctions
Condition: 3+
Apr 24, 2026
$26,320
Bonhams Cars
Condition: 3+
Jan 29, 2026
$38,379
Artcurial
Condition: 2
Jan 27, 2026
$59,721
Bonhams Cars
Condition: 3+
Sep 5, 2025
$32,552
Bonhams Cars
Condition: 3+
Jul 12, 2024
$40,240
Gooding & Co.
Condition: 2-
Apr 26, 2024
$42,560
Bonhams Cars
Condition: 2+
Jun 4, 2023
$35,840
Worldwide Auctioneers
Condition: 3
Apr 28, 2023
$28,000
Broad Arrow Auctions
Condition: 2+
Mar 3, 2023
$89,600
Bring a Trailer
Condition: 3
Jan 30, 2023
$47,250
Bonhams
Condition: 3
Jul 3, 2022
$23,913
Bonhams
Condition: 3
Jan 27, 2022
$44,800
Gooding & Co.
Condition: 2
Jan 18, 2021
$203,500
Artcurial
Condition: 3+
Jul 21, 2020
$47,740
RM Sotheby's
Condition: 2
Jan 16, 2020
$64,400
Mecum Auctions
Condition: 3+
Aug 15, 2019
$50,600
RM Sotheby's
Condition: 2
Apr 11, 2019
$75,131
Bonhams
Condition: 2-
Feb 7, 2019
$49,578
Bonhams
Condition: 2-
Aug 24, 2018
$95,200
Lucky Collector Car Auctions
Condition: 3-
Aug 24, 2018
$13,750
Bonhams
Condition: 3
Mar 8, 2018
$30,000
Silverstone
Condition: 2-
Jul 30, 2016
$54,814
Artcurial
Condition: 3
Feb 5, 2016
$25,370
Bonhams
Condition: 3+
Sep 26, 2015
$56,729
Auctions America
Condition: 3+
Sep 2, 2015
$38,500
Bonhams
Condition: 3
Jun 26, 2015
$97,473
Artcurial
Condition:
Feb 7, 2014
$35,596
Artcurial
Condition: 3
Feb 7, 2014
$744,290
Artcurial
Condition:
Oct 20, 2013
$24,700
Bonhams
Condition: 3-
Oct 11, 2013
$15,595
Artcurial
Condition: 2-
Jun 10, 2013
$79,473
Leake
Condition: 3
Jun 9, 2013
$21,450
Artcurial
Condition: 1
Feb 8, 2013
$170,652
Coys
Condition: 3-
Jan 12, 2013
$22,833
Artcurial
Condition: 3
Jul 7, 2012
$135,658
Artcurial
Condition: 2
Feb 3, 2012
$34,492
Gooding & Co.
Condition: 2
Aug 14, 2010
$50,600
Bonhams
Condition: 2-
Feb 7, 2009
$250,905
eBay
Condition: 3-
May 28, 2007
$6,200
Artcurial
Condition: 2+
Feb 19, 2007
$34,335
Worldwide Auctioneers
Condition: 4
Dec 10, 2005
$24,800
Mecum Auctions
Condition: 4
May 26, 2005
$6,300
Barrett-Jackson
Condition: 3
Jan 22, 2004
$15,120
Barrett-Jackson
Condition: 3+
Jun 15, 2001
$10,260
Bonhams & Brooks
Condition: 1-
May 21, 2001
$25,570
Spectrum
Condition: 3+
Apr 1, 2001
$22,050
Bonhams
Condition:
Feb 7, 2009
$22,253