Engine Mitsubishi 3B21

The 1.0-liter 3-cylinder Mitsubishi 3B21 engine was assembled in Japan from 2006 to 2014 and installed on the second generation of the W451 Smart Fortwo model, popular in Europe. Such a power unit according to the nomenclature of the Daimler-Chrysler concern is known as the Mercedes M132.

The 3B2 family also includes engines: 3B20, 3B20T and 3B21T.

The engine was installed on:

  • Smart Fortwo 2 (W451) in 2006 – 2014.


Production years 2006-2014
Displacement, cc 999
Fuel system distributed injection
Power output, hp 61 – 71
Torque output, Nm 89 – 92
Cylinder block aluminum R3
Block head aluminum 12v
Cylinder bore, mm 72
Piston stroke, mm 81.8
Compression ratio 11.4
Features DOHC
Hydraulic lifters no
Timing drive chain
Phase regulator MIVEC
Turbocharging no
Recommended engine oil 5W-30
Engine oil capacity, liter 3.3
Fuel type petrol
Euro standards EURO 4/5
Fuel consumption, L/100 km (for Smart Fortwo 2008)
— city
— highway
— combined
Engine lifespan, km ~200 000
Weight, kg 67 (without attachments)

Disadvantages of the Mitsubishi 3B21 engine

  • The engine exists in two versions and a simple modification does not cause trouble;
  • In the MHD hybrid, the starter-alternator belt warps and wears out quickly;
  • A broken belt causes the pump to stop and the head immediately leads due to overheating;
  • By 100,000 km, the rubber rings on the candle wells are tanned and oil gets there;
  • There are no hydraulic lifters and valve clearances need to be adjusted every 100,000 km.

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