Engine BMW N52B25 under the hood

Engine BMW N52B25

The 2.5-liter N52 engine of the N52B25 series has six cylinders arranged in one row. Its production began in 2005, in which it replaced the M54B25. Compared to the previous M-series engines, the engine is completely different. The engine uses an aluminum-magnesium alloy cylinder block. Aluminum alloy was used as a liner material, cylinder liners are made of alusin, which, when the internal combustion engine is operating, gives a durable silicon coating of the cylinder walls. The connecting rod-piston group has become lighter and the crankshaft has changed.


Manufacturer Munich Plant
Also called N52
Production years 2005-2011
Cylinder block alloy magnesium/aluminum
Fuel system injector
Configuration inline
Number of cylinders 6
Valves per cylinder 4
Piston stroke, mm 78.8
Cylinder bore, mm 82
Compression ratio 11
Displacement, cc 2497
Power output, hp 177/5800 / 204/6400 / 218/6500
Torque output, Nm / rpm 230/3500-5000 / 250/2750-3000 / 250/2750-4250
Fuel type 95
Euro standards Euro 5
Weight, kg ~120
Fuel consumption, L/100 km
— city
— highway
— combined
Oil consumption, gr/1000 km up to 1000
Recommended engine oil 5W-30 / 5W-40
Engine oil capacity, liter 6.5
Amount of engine oil for replacement, liter ~6.0
Oil change interval, km 10000
Normal engine operating temperature, °C ~95
Engine lifespan, km
— official information
— real


Frequent problems

The main problems of the N52B25 engine are: increased oil consumption, ticking sounds, floating revs.

High oil consumption is usually associated with oil scraper rings. They are very thin and coke quickly enough. The reason may be in the valve stem seals. The problem appears even before reaching the mark of 100 thousand kilometers. The condition of the system should be checked regularly and the rings and caps should be replaced. It is also recommended to check the condition of the KVKG – crankcase ventilation valve.
Engine BMW N52B25
If you do not pay attention to the high oil consumption, the existing problem will lead to clogging of the catalysts. In this case, it will be necessary to supply new catalysts, which will be expensive, or use inexpensive flame arresters.

When a ticking sound is heard in the engine, these are features of power units manufactured before 2009. This does not pose any danger to the unit.

Floating revolutions occur due to a breakdown of the Valvetronic system, Vanos valves or a flow meter. If not properly maintained, the Vanos system can lead to problems. System failure is usually caused by the use of low-quality working fluids. To restore system operation, a flush is performed. If the problem persists, a replacement is required.

If the engine overheats, check the condition of the cooling system, pump, cleanliness of the radiator. The pump needs to be changed every 100 thousand kilometers. The oil recommended by the manufacturer should be used.

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