Engine BMW N46B20

BMW N46 gasoline engines were produced from 2004 to 2015 and were installed on almost all compact and medium-sized models of the group of that time. The 2.0-liter N46B20 engine was created on the basis of the N42B20 and at first glance does not differ from its predecessor, but it is not.

The differences between the BMW N42 and the N46 are as follows: a different crankshaft, balancer shafts, connecting rods and a cylinder head cover, a redesigned intake manifold, a modified timing chain tensioner, new spark plugs and a generator, a Valvetronic control unit integrated into the ECU and some other little things. Otherwise, this is the same N42 with its pluses and minuses. Bosch ME 9.2/Bosch MV17.4.6 engine management system.

Since 2007, the engine has been slightly upgraded, the intake manifold and exhaust camshaft have been replaced, the new modification was called the N46N.

This motor was used on BMW cars with an index of 18i and 20i.

Specifications

Production years	2004-2012 BMW Plant Hams Hall
Displacement, cc	1995
Fuel system	injector
Power output, hp	129 – 150 143 – 170 (N46N)
Torque output, Nm	180 – 200 190 – 210 (N46N)
Cylinder block	aluminum R4
Block head	aluminum 16v
Cylinder bore, mm	84
Piston stroke, mm	90
Compression ratio	10.5
Features	Valvetronic
Hydraulic lifters	yes
Timing drive	chain
Phase regulator	double VANOS
Turbocharging	no
Recommended engine oil	5W-30
Engine oil capacity, liter	4.25
Fuel type	petrol
Euro standards	EURO 4/5
Fuel consumption, L/100 km (for 320i E90) — city — highway — combined	10.7 5.6 7.4
Engine lifespan, km	~300 000

Disadvantages of the N46B20 engine

1. Excessive consumption of engine oil. As with the N42 series, the main reason is the destruction of the valve stem seals due to prolonged filling of low-quality oil. The oil scraper rings also suffer from this. Both components need to be replaced after 50 thousand kilometers. Bad oil can easily damage the Vanos and Valvetronic systems, crankcase ventilation valve and the oil pump.
2. Motor jitter. The system for changing the valve timing is clogged – Vanos. Cleaning required.
3. The appearance of noise and diesel effect. The same reasons as on the N42 version are a loosening of the timing chain or a breakdown of its tensioner. Such ailments appear already after passing 100 thousand kilometers.

Fifty thousand kilometers of run can be marked by leaking valve cover gaskets and vacuum pump. To avoid most of the engine malfunctions and to make it work harmoniously, like a good clockwork, you can, if you constantly monitor its condition, undergo maintenance on time and fill it with only good oils and fuel.