The BMW N53 is a non-supercharged inline six-cylinder gasoline engine that was produced from 2006 to 2013. The N53 atmospheric engine replaced its predecessor, the N52, and debuted in 2006 in the updated BMW E60 5 Series. The N53 was available in two variants, the N53B25 with a displacement of 2.5 liters (2,497 cc) and the N53B30 with a displacement of 3 liters (2,996 cc).
BMW never sold the N53 engine in cars for the North American, Australian and Malaysian markets due to the high sulfur concentration in the fuel of these countries. Instead, its predecessor, the N52, continued to be used in these regions.
The N53 was the last BMW-built non-injection inline six-cylinder engine, ending the history of continuous production of this engine configuration, beginning with the BMW M30 in 1968. Production of the N53 began to be phased out after the introduction of the turbocharged four-cylinder BMW N20 engine in 2011.
There is no M version of the N53 engine. Along with the N53, the turbocharged inline six-cylinder N54 engine was produced.
Compared to its predecessor, the N53 uses direct fuel injection. The direct injection system uses piezoelectric fuel injectors that inject fuel into the combustion chamber using a layer-by-layer lean mixture. The compression ratio is increased from 10.7 to 12.0:1.
Like the N52, the N53 has dual VANOS (variable valve timing system) and a magnesium alloy block. Unlike the N52, the N53 motor does not have Valvetronic (valve lift control) due to lack of space in the cylinder head.
The 85mm cylinder diameter and 88mm piston stroke are the same as the N52. Also, the N53 again utilizes fully electronic ignition coils with coil-on-a-plug ignition coils like the N52.
The engine control unit (DME) is a Siemens MSD81.
Modifications
Depending on the modification, the N53 engine was used in BMW cars with 23i, 25i and 30i:
N53B25 / N53B25UL (190 hp and 235/240 Nm):
2007-2010 BMW E60/E61 523i
N53B30 (204 hp and 270 Nm):
2009-2011 BMW F10 523i
N53B30U0 (218 hp and 270 Nm):
- 2007-2013 BMW E90/E91/E92/E93 325i, 325xi
- 2007-2010 BMW E60/E61 525i, 525xi
N53B30 (258 hp and 310 Nm):
2010-2011 BMW F10 528i
N53B30O0 (272 hp and 320 Nm):
- 2007-2010 BMW E63 630i
- 2007-2010 BMW E60/E61 530i, 530xi
- 2007-2013 BMW E90/E91/E92/E93 330i, 330xi
- 2011-2013 BMW F10 530i
BMW N53 problems and recommendations
The BMW N53 is not prone to oil build-up compared to its predecessor, but it does have a number of shortcomings, which we’ll cover below.
THE FUEL INJECTION SYSTEM
The N53 uses the same problematic high-pressure fuel pump (HPF) as the turbocharged N54 engine. A failing fuel pump is accompanied by floating idle, engine starting problems, jerky acceleration, and dashboard errors. Because of a faulty fuel injector, the engine was not getting enough fuel to operate properly. Failure of the fuel pump is observed at a mileage of 80-120 thousand kilometers. The solution is to replace the fuel pump with a version of the latest modification.
Fuel injectors
Fuel injectors are also a common problem of the N53 motor. By 100,000 km, faulty injectors are leaking excessive amounts of fuel into the cylinders, causing ignition skips, poor fuel efficiency, rough idling and eventually a Check Engine notification, up to and including emergency mode. The solution is to install 2014 revision piezo injectors.
Ignition System
The traditional problem with this motor is the coils and spark plugs. Signs of failure are ignition misses and uneven idle. Coils wear out by 50 thousand kilometers, but spark plugs are often earlier. It is recommended to change them as a set – six coils and plugs each.
NOx sensor
At high mileage, faulty NOx sensors (nitrogen oxide sensor in the exhaust system) cause uneven idling, ignition misses in the cylinders and engine jerkiness. The solution is to replace the sensor, or remove the catalytic converters with the sensor and then reprogram the ECU to the new operating mode.
Among other N53 failures at high mileage are the following: failure of the water pump, low pressure fuel sensor and in rare cases low pressure fuel pump, as well as failures in the Vanos system and oil leaks from under the gaskets and seals.
What kind of oil should I use in my BMW N53?
BMW LL-01 specification synthetic engine oil with SAE 5W-30 and 5W-40 viscosity is recommended for N53 engines.
In conclusion – is the BMW N53 reliable?
The BMW N53 is a reliable engine with a high life expectancy. This engine has a strong cylinder block, cylinder head and a good cooling system. If you fix the above problems in time, this engine will serve long and trouble-free. N53 likes regular maintenance, is demanding to high-quality engine oil and gasoline.
With timely maintenance every 10 thousand kilometers the N53 engine resource is estimated at 300 and more thousand kilometers of mileage without major overhaul.