The MR is a family of straight-four all-aluminium automobile engines with variable valve timing co-developed by Renault and Nissan. Renault calls it the M engine. Other noteworthy features of this engine family include acoustically equal runner lengths and a tumble control valve for the intake manifold, a "silent" timing chain, mirror finished crankshaft and camshaft journals, and offset cylinder placement in an attempt for increased efficiency.

The MR engine family features 'under stress' manufacture, meaning while the block is being bored, a torque plate puts the block under stress. The block becomes temporarily distorted until the head is torqued onto it, at which point the block is pulled into the correct shape.

The MR18DE is a 1.8 L (1798 cc) version, bore and stroke is 84 mm × 81.1 mm (3.31 in × 3.19 in). It produces 130 PS (96 kW; 128 hp).

In North America the output is 122 hp (91 kW; 124 PS) at 5500 rpm and 174 N⋅m (128 lb⋅ft) at 4800 rpm.

From July 6, 2006 this engine is also fitted to Nissan Livina Geniss for China version and the Nissan Grand Livina for Indonesia and Malaysia. Output is 126 PS (93 kW; 124 hp) at 5200 rpm and 174 N⋅m (128 lb⋅ft) at 4800 rpm.

For Brazil, this engine is fitted to the Tiida and Livina ranges, with Flex-fuel capability.

Applications:

2004–2012 Nissan Tiida/Versa
2006–2019 Nissan Grand Livina
2006–present Nissan Wingroad
2009-2014 Nissan Cube