Engine BMW N46B18

Engine BMW N46B18

The BMW N46 engine is a four-cylinder piston engine with two overhead camshafts, which replaced the N42 and has been in production since 2004. The N46 was produced alongside the N45 (which does not have Valvetronic) and the N43 (which has direct injection). The BMW N46B18 1.8 L (1796 cc) engine produces 114 horsepower (85 kW) at 5500 rpm and 175 Nm of torque at 3750 rpm.


Manufacturer BMW Plant Hams Hall
Also called N46
Production years 2004-2005
Cylinder block alloy aluminum
Fuel system injector
Configuration inline
Number of cylinders 4
Valves per cylinder 4
Piston stroke, mm 81
Cylinder bore, mm 84
Compression ratio 10.2
Displacement, cc 1796
Power output, hp 116/5500
Torque output, Nm / rpm 175/3750
Fuel type 95
Euro standards Euro 4
Weight, kg
Fuel consumption, L/100 km (for 316i E46)
— city
— highway
— combined
Oil consumption, gr/1000 km up to 700
Recommended engine oil 5W-30 / 5W-40
Engine oil capacity, liter 4.25
Oil change interval, km 10000
Normal engine operating temperature, °C
Engine lifespan, km
— official information
— real


Engine BMW N46B18 under the hood

Frequent problems

  1. Increasing the oil rate. The reason lies in the imminent wear of the oil scraper rings and seals due to the filling during operation of low-quality, uncertified or not recommended by the manufacturer of engine oil. A breakdown occurs already at 50 thousand kilometers. In addition, using the wrong base oil leads to malfunctions in Vanos, KVKG, oil pump and many other components.
  2. Vibration. The malfunction of the cleaning of the Vanos system is eliminated.
  3. Noise generation, increased smoke emission. The main reason for the phenomenon is the relaxation of the tensioner or the stretching of the timing chain. A typical problem arises after passing one hundred thousand kilometers.
  4. Leaking gaskets. After the motor has traveled more than 50 thousand km of the track, the gaskets of the valve cover and the vacuum pump begin to flow. Replacement required.

Regular inspection and maintenance, as well as the use of only high-quality components and, above all, fuel and engine oil, will help to maximize the life of the engine and reduce the risk of breakdowns.

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