Also known as: n55b30, 335i engine, 535i engine, 3.0 turbo straight-six, m135i engine
The N54's replacement, and the engine that fixed most of what made its predecessor notorious. One twin-scroll turbocharger instead of two, with Valvetronic variable lift added — a simpler, cheaper and markedly more reliable arrangement carrying the same 3.0-litre displacement and the same badges.
That history is the practical point. N54 fault patterns are repeated about the N55 constantly and most of them do not apply: the high-pressure fuel pump and injector failures that defined the earlier engine are far less common here. Diagnose an N55 on its own evidence rather than on its predecessor's reputation.
What it does bring is a valve-cover and oil-filter-housing gasket that harden and leak with age — often onto the belt or the exhaust, so the first symptom is a smell rather than a level — and the electric water pump, which fails without warning and takes the engine's cooling with it. Carbon on the intake valves remains, as on any direct-injected engine of the era.
Cars fitted with this engine
16 generations, across 1 make. From the authored catalogue — an absent car means the catalogue has not reached it, not that the engine was never fitted.
BMW
- 1 Series E87 2004–2013
- 3 Series E90 2005–2012
- X5 E70 2006–2013
- 7 Series F01 2008–2015
- X6 E71 2008–2014
- X1 E84 2009–2015
- 5 Series F10 2010–2017
- X3 F25 2010–2017
- 1 Series F20 2011–2019
- 6 Series F06, F12 and F13 2011–2018
- 3 Series F30 2012–2019
- X5 F15 2013–2018
- 4 Series F32 2013–2020
- X6 F16 2014–2019
- 2 Series F22 2014–2021
- X4 F26 2014–2018
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
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What makes one worth reading:
- The car — make, model, year and engine. The same fault behaves differently on each.
- What you measured, not only what you replaced.
- What actually fixed it — or that nothing did, which is worth knowing too.
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