Mitsubishi 6B31 engine
This is one of the popular power plants of the Outlander and Pajero Sport car. It is mentioned quite often in the forums. Unfortunately, most of the reviews are related to the peculiarities of its repair. Although, on these grounds, the Mitsubishi 6B31 engine should not be considered unreliable or weak. But more about everything.
Description
Mitsubishi 6B31 has been produced since 2007. A few years later, it is subjected to a major modernization, although the engine receives only 7 liters. With. and 8 newton meters. But it has become noticeably more dynamic, and most importantly, fuel consumption has decreased by 15 percent.
What specifically changed during chip tuning:
- connecting rods were lengthened;
- the shape of the combustion chamber has been changed;
- lightened internal elements;
- reflash the gearbox control unit.
The compression ratio has increased by 1 unit, the torque has been optimized, and the recoil efficiency has improved.
The reliability of the three-liter unit is rarely questioned when compared with other Mitsubishi engines. However, its repair is already inevitable after the 200th mark, and the price of maintenance clearly exceeds the "four". The timing drive is made qualitatively - it is enough just to change the belts and rollers in a timely manner. After a long run, the camshafts can “wipe”, the bed and rocker arms can be damaged.
The oil pump is also at risk. It is good that it is inexpensive - approximately 15-17 thousand rubles for the original product. After the 100th run, it is recommended to check the oil pressure, change the lubricant if necessary. It is noteworthy that oil leakage is one of the popular "sores" not only of the 6B31, but also of all other engines of the manufacturer.
The next items to include in the list of required consumables are pillows. They will have to be changed at every third MOT if the car is actively used and on various road surfaces, including off-road.
Radiators that cool the engine do not last long. Although they do not belong to his details, they work in tandem with him. Therefore, on vehicles equipped with 6B31, it is often necessary to check the condition of the radiators so as not to overheat the engine.
As for the resource of the piston group, it is great. There are no problems with leaks, the oil does not penetrate into the antifreeze. I am glad that there are a lot of contract engines to replace and they are inexpensive.
In general, the engine management system is reliable, but lambda sensors and catalysts behave capriciously, falling apart after a 150th run. If these parts are not replaced in time, then piston scuffing is possible.
| Advantages | Disadvantages |
| Dynamic, low fuel consumption | After 200 thousand km of run, repair is inevitable |
| Improved recoil efficiency | Maintenance cost is high |
| The timing drive is made with high quality | Oil leakage is a common engine problem. |
| The resource of the piston group is large | Weak motor mounts |
| There are many low cost replacement contract engines on the market. | Radiators fail quickly |
| Engine control system is reliable | At risk lambda sensors and catalysts |
| Engine displacement, cc | 2998 |
| Maximum power, hp | 209 – 230 |
| Maximum torque, N * m (kg * m) at rpm. | 276 (28) / 4000; 279 (28) / 4000; 281 (29) / 4000; 284 (29) / 3750; 291(30)/3750; 292 (30) / 3750 |
| Fuel used | Petrol; Gasoline Regular (AI-92, AI-95); Gasoline AI-95 |
| Fuel consumption, l / 100 km | 8.9 – 12.3 |
| engine's type | V-shaped, 6-cylinder |
| Add. engine information | DOHC, MIVEC, ECI-Multi port injection, timing belt drive |
| Number of valves per cylinder | 4 |
| Maximum power, h.p. (kW) at rpm | 209 (154) / 6000; 220(162)/6250; 222(163)/6250; 223(164)/6250; 227 (167) / 6250 |
| The mechanism for changing the volume of cylinders | no |
| Start-stop system | no |
| What cars was installed on | Outlander, Pajero Sport |
Why knocks 6B31: liners
A strange sound coming from the bowels of the engine installation can be observed on a working 6B31 quite often. It is better heard from the passenger compartment, with the climate control turned off and the windows raised. Obviously, it is necessary to muffle the acoustics so that it can be detected.
The nature of the sound is muffled, but distinct. It is heard at speeds above 2 thousand per minute. On deceleration it changes to knocking. The lower the rpm, the less noise. Many 6B31 owners do not notice the noise just because of inattention.
It should also be noted that this sound may be weak at first. As the problem increases, it intensifies, and an experienced motorist will immediately notice it.
If you disassemble the oil pan, you will find metal shavings. Upon closer inspection, you can determine that it is aluminum. As you know, the 6B31 liners are made of this material - accordingly, they either turned around or are trying to do it soon.
For accurate diagnosis, it is recommended to disassemble the motor, since it will be difficult to find a good minder who will determine the problem by this weak sound, especially if the engine's passport resource has not yet been worked out.
6B31 is dismantled along with the box. Removed through the top, the stretcher can not be touched. After dismantling, it is necessary to separate the motor from the box, and continue disassembling. At the same time, you can work on the automatic transmission - cut it in half, replace the filter, clean the magnets.
After the final disassembly of the engine, it will become clear what exactly is knocking. This is one liner on some kind of connecting rod or several repair liners that have become unusable. On 6B31 they often turn over, although the reason is not particularly clear. Most likely, this is due to the low quality of Russian fuel.
If the liners are in order, then you need to continue the search. First of all, check the crankshaft, cylinders and pistons. Valves deserve special attention. When disassembling the cylinder head, defects can be found at the end of one of them. Therefore, it is important to timely adjust the valves.
The list of works should include the following activities:
- replacement of oil scraper caps;
- saddle spice;
- backlash control.
Engine assembly involves connecting to an automatic transmission. Subsequent work must be carried out in reverse order. But there are some features that are important to pay attention to:
- it will be useful to replace the radiator of the variator or automatic transmission;
- be sure to update the lubricant;
- carefully check all the seals, the rubber gasket of the automatic transmission is well docked with the body.
SENSORS
Many different sensors are integrated with the 6B31 motor. Moreover, this is organized on almost all cars equipped with this internal combustion engine. Here are the sensors used:
- DPK - crankshaft position regulator connected to ground;
- DTOZH - always connected, like the DPK;
- DPR - camshaft sensor, connected regularly or during operation at XX;
- TPS - always connected;
- oxygen sensor, with a voltage of 0,4-0,6 V;
- power steering fluid sensor;
- accelerator pedal position sensor, with a voltage of 5 V;
- cruise control sensor;
- DMRV - mass air flow regulator, etc.
6B31 is considered one of the best and most powerful gasoline engines installed on Pajero Sport and Outlander.
