BMW N53

BMW N53 engine
Overview
Manufacturer	BMW, Bayerische Motoren Werke AG
Production	2007–2014
Combustion chamber
Configuration	Straight 6
Chronology
Predecessor	BMW N52
Successor	BMW N20, BMW N55

The BMW N53 is a straight 6 DOHC piston engine which was produced from 2006 to 2011. It is the final naturally aspirated straight-6 engine produced by BMW, ending a history of continuous production of this engine configuration since 1968. The N53 released in 2006 in the facelifted E60/E61 523i and 525i. Following the introduction of the N20 turbocharged straight-4 engine in 2011, the N53 began to be phased out. The N54 turbocharged straight-6 engine was produced alongside the N53, therefore the N54 took over as the highest performance six-cylinder engine.

Compared with its N52 predecessor which was port-injected, the N53 uses direct injection (consisting of Piëzo-electric injectors directly in the cylinder) with a stratified lean mixture operation.^[1] The N53 has variable valve timing on both camshafts (called double vanos by BMW) and a magnesium alloy block.^[2] Unlike the N52, the N53 does not contain variable valve lift (called valvetronic by BMW), due to space limitations in the cylinder head.^[3][4]

BMW never sold the N53 engine in North American, Australian and Malaysian vehicles, due to the high sulphur content of the fuel available in these markets.^[5] These regions continued to use the N52 port-injected naturally-aspirated and N54 direct-injection twin-turbo inline-6 engines for the 2007-2011 model years.

Models

N53B25-U0

The 2.5-litre N53B25-U0 is used in the E60/E61 523i ^[6] and produces 140 kW and 235 Nm.^[4]

Applications:

• 2006-2010 E60/E61 523i

N53B30-U0

The E90/E91/E92 325i switched from the 2.5 litre N52 to the 3.0 litre N53B30-U0 in March 2007. Despite the increased displacement, the maximum power remained unchanged at 160 kW.^[4]

Applications:

• 2007-2011 E90/E91/E92/E93 325i
• 2006-2010 E60/E61 525i
• 2009-2011 F10/F11 523i
• 2009-2011 F10/F11 528i

N53B30-O0

The N53B30-O0 increased power to 200 kW (270 hp) and torque to 320 N·m (240 lb·ft).^[4]

Applications:

• 2007-2011 E90/E91/E92/E93 330i
• 2007-2010 E60/E61 530i

Common Problems

HPFP Failure

The N53 engine shares the High Pressure Fuel Pump with the N54 series of engine and has suffered from the same problems. BMW in Europe have not had to purchase cars under Lemon Laws as they have in the US market, ^[7]. The N53 engine was not sold in the USA, therefore not subject to the same class action legal threats and buy-backs as detailed below on the N54 engine. In the US BMW have extended the fuel pump warranty to 10 years ^[8], BMW Europe instead have left owners unsupported with no extension to warranty or goodwill gestures.

In at least the US market, the N54 engine has been characterized by a very large number of High Pressure Fuel Pump (HPFP) failures,^[9] leading to BMW North America vehicle Lemon Law "buy backs" and reduced customer goodwill.^[10] BMW's failure to solve the HPFP problem has led to serious safety concerns over dangerous sudden losses of power at highway speeds.^[10] Reports of drivers being stranded are not uncommon and some have accused BMW of actively concealing the problem rather than addressing it.^[10] On 26 October 2010, BMW announced a recall of vehicles with the pump in question from manufacturing years 2007–2010.^[11]

In April 2009, a class action suit was filed against BMW in connection with HPFP failures.^[12] BMW settled the suit in June 2010. On 26 October 2010, following an ABC News story about HPFP failures,^[13] BMW announced a recall of vehicles with the pump in question from manufacturing years 2007-2010.^[14]

Direct Fuel Injectors

Direct injection is used within the N53 engine. With fuel avoiding the inlet manifold carbon can build up requiring this to be cleaned. Injector failure is also common, causing either rough running, engine faults or general loss in power^[15].

Coil Packs

Each cylinder has an individual coil to create a spark for the plug. These are known failure^[16]

Extended BMW Warranty

Due to many quality failures by BMW for the sister N54 engine, they have been forced for the USA market to extend the warranty on the High Pressure Fuel Pump and also the Injectors to 10 years. ^[17]. Owners in other regions are left without support.

No such extension exists for the N53 engine as it was not sold in the USA. BMW are not supporting owners of the N53 engine.

See also

• BMW N52
• BMW N54
• BMW engines
• BMW vehicles

References