BMW N53

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BMW N53 engine
530i Touring Msport LCI 59.JPG
Overview
Manufacturer BMW, Bayerische Motoren Werke AG
Production 2007–2014
Layout
Configuration Straight 6
Chronology
Predecessor BMW N52
Successor BMW N20, BMW N55

The BMW N53 is a naturally aspirate straight-6 petrol engine which was produced from 2006 to 2011. The N53 replaced the N52 and was released in 2006 in the post-facelift E60/E61 523i and 525i.

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.[1] 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.

The N53 is the final naturally aspirated straight-6 engine produced by BMW, ending a history of continuous production of this engine configuration since the M30 in 1968. The N53 was replaced by the N20 turbocharged straight-4 engine in 2011.

There is no M version of the N53. The N54 turbocharged straight-6 engine was produced alongside the N53.

Design[edit]

Compared with its N52 predecessor which was port-injected, the N53 uses direct injection (consisting of piezoelectric injectors directly in the cylinder) with a stratified lean mixture operation.[2] The N53 has variable valve timing on both camshafts (called double vanos by BMW) and a magnesium alloy block.[3] Unlike the N52, the N53 does not contain variable valve lift (called valvetronic by BMW), due to space limitations in the cylinder head.[4][5]

Models[edit]

Engine Code Displacement Power Torque Bore Stroke CR Year
N53B25-U0 2,497 cc (152 cu in) 140 kW (190 hp) @ 6100 rpm 235 N·m (173 lb·ft) @ 3500-5000 rpm 82.0 78.8 12.0 2007
N53B30 2,996 cc (183 cu in) 150 kW (200 hp) @ 6700 rpm 270 N·m (200 lb·ft) @ 1500-4250 rpm 85.0 88.0 12.0 2010
N53B30-U0 160 kW (210 hp) @ 6100 rpm 270 N·m (200 lb·ft) @ 2400-4200 rpm 85.0 88.0 12.0 2007
N53B30 200 kW (270 hp) @ 6100 rpm 310 N·m (230 lb·ft) @ 1600-4250 rpm 85.0 88.0 12.0 2010
N53B30-O0 200 kW (270 hp) @ 6700 rpm 320 N·m (240 lb·ft) @ 2750-3000 rpm 85.0 88.0 12.0 2007

N53B25-U0[edit]

The 2.5-litre N53B25-U0 is used in the E60/E61 523i [6] and produces 140 kW and 235 Nm.[5]

Applications:

N53B30-U0[edit]

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.[5]

Applications:

N53B30-O0[edit]

The N53B30-O0 increased power to 200 kW (270 hp) and torque to 320 N·m (240 lb·ft).[5]

Applications:

Common Problems[edit]

HPFP Failure[edit]

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 have not offered any 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]

In April 2009, a class action suit was filed against BMW in connection with HPFP failures.[11] BMW settled the suit in June 2010. On 26 October 2010, following an ABC News story about HPFP failures,[12] BMW announced a recall of vehicles with the pump in question from manufacturing years 2007-2010.[13]

Direct Fuel Injectors[edit]

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[14].

Coil Packs[edit]

Each cylinder has an individual coil to create a spark for the plug. These are known to be prone to failure[15]

Extended BMW Warranty[edit]

Due to many quality failures by BMW for the sister N54 engine, they have been forced for the United States market to extend the warranty on the High Pressure Fuel Pump and also the Injectors to 10 years. [16] Owners in other regions do not receive any warranty extension.

Even though many of the failure prone parts are shared between the N53 and N54 engines, no such extension is being offered for the N53 engine by BMW as it was not sold in the United States.

See also[edit]

References[edit]