The OM656 is a turbocharged diesel engine produced by Mercedes-Benz since 2017.

[1] The OM656 is based on a modular design that is shared with other 4-cylinder and 6-cylinder, petrol and diesel engines.

[2] It is the replacement to the previous V6,[3] in order to maintain the cost of production between different engines.

The OM656 has dual overhead camshafts with variable valve timing, and uses AdBlue injection and exhaust gas recirculation to reduce emissions.

[4] The cylinder walls are coated with arc sprayed steel whose increased porosity aids oil film strength to reduce friction.