Which Mercedes diesel engine is the most reliable?

The 2.0 OM654, fitted to d models since 2016, is regarded as the brand's toughest recent diesel. The earlier 2.1 OM651 is durable too, but early units had timing chain and injector problems.

Does a used Mercedes diesel need AdBlue?

Yes, BlueTEC and nearly all recent d models carry AdBlue in a separate tank that needs topping up now and then. If the system fails or the tank runs dry, the car warns you and may refuse to restart.

Is a Mercedes diesel worth it for city driving in Portugal?

Rarely, unless you also cover regular motorway miles. Short trips clog the particulate filter, and diesel passenger cars in Portugal pay an extra IUC surcharge.

Cars

Used Mercedes diesel cars in Portugal

Found 7,856 cars

From €800 to €255,800, half under €21,990 · Typically 2017 with 152,558 km · Most listed: Mercedes-Benz C-Class, Mercedes-Benz A-Class, and Mercedes-Benz CLA-Class. Diesel still powers most used Mercedes in Portugal, from the A 180 d to the E 220 d. The engines moved from CDI to BlueTEC and then d badges, adding AdBlue and a particulate filter that wants open-road driving.