Engine code
N45 · 1.6 liter (N45B16) and 2.0 liter (N45B20) · 4-cylinder, no Valvetronic · 2003-2011 in BMW's parts catalog · 116i, 316i, 316Ci, 316ti, 320si
The N45 is the redesigned 1.6 liter N40, the basic engine of the E87 1 Series, with double VANOS and a conventional throttle instead of Valvetronic. BMW's workshop data also lists a 2.0 liter N45B20 for the E90, and BMW's parts catalog lists the N45 code for the E90 320si. The N45 was not sold in US-market BMWs, per BMW's own vehicle lists (data to December 2019), so this is a short guide.
This guide only states what BMW's own documents establish. Ownership opinions, failure rates, costs and tuning potential are marked as not established.
N45 At a Glance
| Question | Practical answer |
|---|---|
| Where you find it | E87 and E81 116i; E46 316i, 316Ci and 316ti; E90 316i and 320si. BMW's service documents say the N45 is the basic E87 engine for all countries. |
| Catalog window | BMW's parts catalog lists catalog dates from 03/2003 to 12/2011; BMW's exhaust overview puts the E87 start at 06/2004. Treat start years as approximate. |
| Sold in US-market BMWs | Not sold in US-market BMWs, per BMW's own vehicle lists (data to December 2019). All 17 N45 and N45N vehicle types BMW lists are for the Europe-catalog market. |
| Engine sizes | 1.6 liter N45B16 and 2.0 liter N45B20 |
| Factory output | N45B16: 85 kW and 150 Nm. N45B20: Not established yet. |
| Valvetronic | No. BMW states the N45B16 has no Valvetronic and no differential air intake control (DISA). The N46 does have Valvetronic. |
| Later version | N45TU2 (technical update 2), introduced 03/2007 in the E87 and E90 and 09/2007 in the E81. |
| Engine oil | 4.25 liters with a new filter. Check the owner's manual for the grade; BMW's current oil suitability list includes the N45. |
| Reliability, cost to own, power potential | Not established yet. We are still researching this engine. |
Technical Specifications
| Specification | Detail |
|---|---|
| Cylinders | 4, petrol |
| Displacement | N45B16: 1,596 cc. N45B20: 1,996 cc. |
| Bore x stroke | N45B16: 84 x 72 mm. N45B20: 85 x 88 mm. |
| Compression ratio | N45B16: 10.2:1 (10.25 in workshop data). N45B20: 11:1. |
| Maximum engine speed | N45B16: 6,500 rpm, constant speed 6,300 rpm. N45B20: 7,300 rpm, constant speed 6,500 rpm. |
| Valvetrain | Double VANOS. No Valvetronic and no DISA on the N45B16. |
| Power and torque | N45B16: 85 kW and 150 Nm |
| Engine management | Digital engine electronics ME 9.2 on the N45B16 |
| Knock control | Yes |
| Secondary air system | No |
| Emissions | BMW's exhaust overview lists the E46 N45B16 as Euro 3 until 03/2005 and Euro 4 from 03/2005, and the E87 as Euro 4 from 06/2004; BMW's engine data table lists Euro 3 for the N45B16. Which applies to a given car is not established. |
| Engine oil capacity | 4.25 liters with filter change |
| Oil level check | No dipstick on the E87, E90 and E91 petrol engines; the level is checked electronically through the instrument cluster menu. |
| Coolant, firing order | Not established yet |
What Changed From the N40
BMW's N45/N46 documentation lists these changes against the N40 and N42: spark plugs with a modified centre electrode, a cast crankshaft, a sheet-metal drag arm, geometrically modified connecting rods, a modified cylinder head cover, and profile-milled drive gears on the balance shaft. On the N45B16 a suction-jet pump supplies the brake vacuum, while the N46 uses a mechanical vacuum pump.
Known Failure Points and Service Items
Not established yet. We found no BMW recall, technical bulletin or training document that names a specific N45 defect. The US recall database does not apply because the engine was not sold in the US.
Reliability Verdict, Power Potential, Cost of Ownership
Not established yet. We are still researching this engine.
Common Questions
What BMW has the N45 engine?
The N45 is the 1.6 liter engine in the 116i (E81, E87) and in the 316i, 316Ci and 316ti (E46) and 316i (E90), and BMW's parts catalog also lists the N45 code for the E90 320si. It was not sold in US-market BMWs, per BMW's own vehicle lists (data to December 2019).
What is the difference between the N45 and the N46?
BMW says the N45B16 has no Valvetronic and no differential air intake control, while the N46 has Valvetronic. The N45B16 makes 85 kW and the N46B20 makes 105 kW in the E46.
How much oil does an N45 take?
BMW's workshop data gives 4.25 liters for an oil change with a new filter element.
Does the N45 have a dipstick?
Not in the E87, E90 and E91. BMW says the petrol engines in those cars check the oil level electronically through the instrument cluster.
Sources
- BMW service documentation, engine control for N45 and N46 (11 01 04 (068)), with the engine-specific data enclosure for the N45 and N46.
- BMW E87 1 Series overview and the exhaust system overview for N40, N42, N45 and N46.
- BMW workshop technical data for the N45 and N45B20, group 11: engine in general, oil supply.
- BMW parts catalog, data date 12 December 2019 (vehicle types, build dates).
- BMW oil suitability list for BMW Group engines, edition 09/2025.
