As illustrated under production numbers, SM sales declined starting in 1972. This appears to be attributable to maintenance issues. Like an exotic Italian car, the Weber carburetors require frequent adjustment. Many engines experienced failure at 60,000 km – it was unclear to most owners that the interference engine design has timing chains that require manual adjustment, an issue not corrected until long after production ceased.Citroën SM' Osprey Autohistory, Jeff Daniels, 1981, The 90° engine timing was unfamiliar to mechanics in the 1970s. Only Buick (1962–66; 1975–) and Jeep (1966–71) used a V6 with 90° between banks of cylinders. Another issue that has been resolved with retrofit is the unreliable ignition breaker cassettes.
As illustrated under production numbers, SM sales declined starting in 1972. This appears to be attributable to maintenance issues. Like an exotic Italian car, the Weber carburetors require frequent adjustment. Many engines experienced failure at 60,000 km – it was unclear to most owners that the interference engine design has timing chains that require manual adjustment, an issue not corrected until long after production ceased.Citroën SM' Osprey Autohistory, Jeff Daniels, 1981, The 90° engine timing was unfamiliar to mechanics in the 1970s. Only Buick (1962–66; 1975–) and Jeep (1966–71) used a V6 with 90° between banks of cylinders. Another issue that has been resolved with retrofit is the unreliable ignition breaker cassettes.