North America
For 1968 MY, Mercedes-Benz offered the W115 220 and 220 D and the W114 230. Those models replaced the previous generation W110 200, 200 D, and 230. The external changes to the US model were the headlamps that housed the sealed beam headlamps and the larger turn signal indicators below the headlamps in place of the integrated fog lamps, inside the bezel of the European models. The fog lamps were separate units attached to the top of bumpers between the headlamps and cooling grille. The side running lamps and retro-reflective markers were attached to the front and rear fenders.
For 1970 MY, the emission regulations led to changes in engine options due to the reduced performance. The 230 with six-cylinder M180 engine was superseded by the 250 with 2.5-litre M114 engine. This car was offered with 4-speed automatic transmission only. Manual transmission option would be eliminated for the 220 with the four-cylinder M115 engine in the following model year. This coincided with release of the W114 Coupe in mid-1969. In Europe it was available as the 250 C and 250 CE with the new D-Jetronic system, but this was not made available for the United States. Instead, a middle ground was chosen by giving a larger displacement 2.8 litre M130 motor, whilst keeping the '250' badging.
For 1971 MY, the 220 with four-cylinder M115 engine was available with automatic transmission only. Also for 1971 Mercedes-Benz replaced the M114 engine with the larger 2.8-litre M130 engine as to compensate for the small performance loss in the 250 sedan.
For 1973 MY, the bumpers had the front bumper guards and secondary bumpers from coupé models. When the bumper regulations were changed in 1974, the W114/W115 received massive 5-mph "battle ram" bumpers. Their heavy weight affected the performance and dynamism of W114/W115. The further changes to the emission regulations led to the replacement of M130 engine with DOHC 2.7-litre M110 six-cylinder engines, replacing the 250 and 250 C with the 280 and 280 C.
A major facelift of W114/W115 in 1974 also changed the engine and transmission options. The 220 was replaced by 230 with M115 engine enlarged to 2.3 litres. For the US market, Mercedes-Benz did not use 230.4 designation as the 2.3-litre six-cylinder engine wasn't offered in the US (The European market had both 230.4 and 230.6 as to differentiate between four and six cylinders). The 220 D with 2.2-litre OM615 diesel engine was superseded by 240 D with larger 2.4-litre OM616 diesel engine and was the only Mercedes-Benz model still available with the manual transmission option.
For 1975 MY, a new engine option, 3-litre OM617 diesel engine with five cylinders was offered in the United States as 300 D. The European model used 240 D 3.0 designation. During 1976, the final year for W114/W115 in the US, the model range was 230, 240 D, 280, 280 C, and 300 D, before being replaced by the W123 in 1976 for 1977 model year.
Given the ever stringent emission control in USA, the cars' performance became significantly handicapped as engines struggled to meet regulations whilst mandatory equipment and 5 mph bumpers would see a continuous increase in their weight. For example the carburettor fed 1973 M110 engine made 160 hp at 5500 RPM and 226 Nm at 4000 under the net DIN rating (180 hp / 248 Nm at 5750/4250 RPM per SAE gross rating) in Europe. The corresponding American export made 132 hp at 5000 and 203 Nm at 3500 SAE net. By 1975 this would collapse to 122 hp at 4800 and 194 Nm at 2800 SAE net. In parallel the 280C's curb weight rose from 1490 kg in 1973 to 1510 in 1974 and finally to 1565 kg for 1975-76. The European 280C remained at 1455 kg from 1973-76.
