The GL 320 CDI is propelled by a V6 diesel powerplant taken from the latest generation of engines. It employs the frugal common-rail direct injection principle which uses piezoelectric injectors to ensure high-precision fuel metering and injection timing. Engine refinement has also undergone a number of advances compared to a conventional diesel unit; the chain routing has been optimised, for instance, resulting in yet smoother running, while noise levels have been subdued by the restyled engine cover.
All of which equates to an exceptional power output of 165 kW (224 hp). Just like its sibling in the GL 420 CDI, the engine is of course equipped with a particulate filter to meet the EU4 emission limits.
The GL 420 CDI is powered by a newly developed V8 diesel engine with a four-valve-per-cylinder design and common-rail direct injection. 225 kW (306 hp) and 700 Nm of torque ensure sporty progress combined with pleasing fuel consumption.
(GL 320 CDI: fuel consumption combined: 9.8–10.0 l/100 km, CO2 emissions combined: 261–264 g/km; GL 420 CDI: fuel consumption combined: 11.6–11.8 l/100 km, CO2 emissions combined: 307–313 g/km)
 The figures are not based on an individual vehicle and do not constitute part of the product offer; they are provided solely for purposes of comparison between different vehicle models