The Most Common 3.0 Mitsubishi 6B31 Mivec Engine Problems

The Most Common 3.0 Mitsubishi 6B31 Mivec Engine Problems

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By Scott Matthew

The 3.0 6B31 Mivec engine was installed on the well-known Outlander and Pajero Sport SUVs from Mitsubishi.

The first version of the 6B31 engine has been produced by Mitsubishi since 2007.

However, a few years after that, it was seriously modernized. As a result, the internal combustion engine received an additional with 7 liters.

In addition, its fuel consumption has decreased by 15%, the compression ratio has increased, and the recoil efficiency has increased.

Read Also: The Most Common 6G73 2.5 GDI Cyclone V6 Engine Problems

6B31 engine Specifications

Volume (cm3)2998
Power (hp)220-230
Torque276 – 291 Nm
Timing driveBelts
Environmental classEuro 4
Fuel typeGasoline AI-92
ICE featuresNot
Supply systemInjector
Hydraulic liftersYes
Cylinder blockAluminum V6
Cylinder headAluminum 24v
Cylinder diameter87.6 mm
piston stroke82.9 mm
Compression ratio9.5-10.5
Phase regulatorMIVEC
Engine oil4.5 l 5W-30
Average resource300 000 km

Reliability and main advantages of the 6B31 engine

  1. 6B31 engine is a modern 3-liter gasoline engine with a maximum power of 209 to 230 hp.
  2. The cylinder block and cylinder head in this engine are aluminum. There are six cylinders, by the way, and their layout is V-shaped.
  3. The 6b31 also uses the MIVEC variable valve timing system, ECI-Multi multi-point injection and a high-quality timing belt drive.
  4. The engine is of the DOHC type, that is, it is equipped with a mechanism with two camshafts.

Disadvantages and problems of the 6B31 engine

  1. This of the 6B31 engine can be called reliable, but after a run of 200,000 kilometers, its repair is almost inevitable.
  2. On such engine, the rocker arms and the oil pump may well be damaged. Moreover, problems with the pump naturally lead to oil leaks (this trouble, by the way, is typical for almost all Mitsubishi engine).
  3. Plus, owners of cars with a of the 6B31 engine experience a strange thud coming from the insides of the engine at rpm above 2000 per minute. The reason for this knock, as a rule, are the liners that have become unusable.

Applicability of The 6B31 engine

  • Mitsubishi : Outlander (2006-), Pajero Sport (2010-)

6B31 Engine Tuning prospects

To chip the 6B31 engine is a completely normal solution. But since the 6B31 belongs to the class of atmospheric engines, you should not expect a large increase in power from this procedure.

Although, of course, there will be positive results – in particular, the interaction of the internal combustion engine with the gas pedal will become more convenient for the driver.

In addition, the dynamics in urban driving will be noticeably better.

The 6B31 engine can also be tuned by replacing and changing some parts.

Among other things, as part of such tuning, connecting rods are enlarged, the configuration of the combustion chamber is changed, pistons are lightened, etc.

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