5 Common Problems With The BMW N54 Engine

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kingr
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5 Common Problems With The BMW N54 Engine

Post by kingr » Wed Sep 11, 2019 4:57 pm

Arguably one of the best and most tunable engines (considered the German 2JZ) BMW has ever produced, the turbocharged straight-six petrol engine N54 has also been housed in some of BMW’s most beloved models of the mid-2000s. First introduced back in 2006, the N54’s quality spanned a decade and ended its career with the 2016 E89 Z4 - a testament to its prolific adaptability and performance. Despite being phased out and replaced with its N55 successor, the N54 holds a special place in the hearts of BMW fans and remains highly sought-after among drivers. However, issues have plagued the N54, and despite being housed in multiple models, the problems have a commonality.

It's essential to take note that the “common” problems arising with the N54 engine are general and may differ across models. Some issues may be inevitable, but they are easily avoidable. Here are five common problems with the BMW N54 engine and the potential cost of repair and replacement.

Introduction:

So why does the N54 occupy the mantle of BMW’s engine trophy cabinet? In 1973, BMW was at the forefront of turbo technology and was the first German manufacturer to bring mass-produced turbocharged petrol engines to the market - General Motors tried in the ’60s but quickly rolled back production. BMW’s first attempt spawned the iconic 2002ti - its first turbocharged production car and arguably pioneered the “sports sedan” segment. The straight-four 2.0L turbocharged petrol engine produced 240 Nm (177 ft·lb) and 125kW of output with a stated 0-100 time of 7.3 seconds. The high engine power came at the expense of poor reliability, high fuel consumption and against the backdrop of the 1973 oil crisis. Turbo technology shifted to diesel engines, with Mercedes-Benz’s 300D and VW’s Golf Turbodiesel considered breakthroughs in the passenger car market. BMW’s first six-cylinder turbocharged, the M106/M102, also seemingly became it's last with production ending in 1986 with the E21 723i.

Fast forward to the 2006 Geneva Motor Show, with BMW’s second crack at a six-cylinder turbocharged petrol engine. Not only does the N54 win every engine-related accolade, but it also leaves the car show as a crime scene and dominates for a decade. The N54 six-cylinder engine was first introduced in 2007 with the 335i E90 generation - which unsurprising became BMW’s best-selling car.

The N54’s career spanned a decade and became BMW’s go-to engine for every x35i variant of the 1,3,5 and x6 series among others. Reviewers at the time noted that, despite being significantly smaller than the 4.2L naturally aspirated 550i, the N54 E60 535i was only “marginally slower” and benefitted from an incredible amount of handling compared to the hulky V8. The quality of the turbocharger was described as “in feel and sound the twin-turbo could pass for naturally aspirated". Building on its direct-injection Double-Vanos variable valve timing system and BMW’s utilization of a twin-scroll low-pressure turbocharger had reduced the dreaded turbo-lag remarkably and is still well regarded for its linear power delivery.

While BMW had formally ended production in 2016, the N54 hasn’t retired to bask in the glory of its five-time International Engine Of The Year trophies and hung-up its gloves just yet. The N54 is still in high demand, and despite being replaced by the N55, many drivers who upgraded have gone back to the N54’s. But even prized fighters have their weaknesses. The N54’s golden record has some black marks with some issues ranging from the superficial to the mechanical defect-kind. Some problems seemed to be shared by multiple drivers and others being strangely localized.

Technical Specifications:

Here’s a brief breakdown of the engine, technical specifications and the models that the N54 engine runs. If you’re unsure whether your BMW has the N54 engine, the most reliable and accurate way is to do a VIN check.

Production: 2006 - 2016

Engine Name: N54B30 (N54)

Configuration: Straight-6

Displacement: 3.0L, 2,979 cc (181.8 cu in)

Valvetrain: DOHC, with VVT, 4 Valves Per Cylinder

Piston Stroke: 89.6mm (3.53 inches)

Cylinder Bore: 84mm (3.3 inches)

[b]Compression Ratio:[/b] 10.2

Turbocharger: Twin-turbo (single twin-scroll), 2 x Mitsubishi TD03-10TK3

ECU: Siemens MSD80

Fuel Type:
Petrol

Recommended Oil Change Interval: 7,000 to 10, 000
Recommended Engine Oil: 5W -30, 5W-40

Engine Versions:

225 kW (302 bhp), 400 N⋅m (295 lb⋅ft) at 1,300-5,000 rpm
240 kW (322 bhp), 450 N⋅m (332 lb⋅ft) at 1,500-4,500 rpm
250 kW (335 bhp), 450 N⋅m (332 lb⋅ft) at 1,500-4,500 rpm


Model Applications:

225kW: 2006–2010 E90/E91/E92/E93 335i
2007–2010 E60/E61 535i
2007–2010 E82/E88 135i
2008–2010 E71 X6 xDrive35i
2009–2016 E89 Z4 sDrive35i

240kW:
2008–2012 F01 740i
2011–2013 E92/E93 335is

250kW:
2011 E82 1 Series M Coupe
2011–2016 E89 Z4 sDrive35is

5 Common Problems With N54 Engine:

Any problem in general associated with the N54 engine has extensive and proactive forums that will give you a host of information if the problem you have isn’t specified below. If you’re still struggling, use our Q/A where our community members will be more than willing to help.

1) High-Pressure Fuel Pump (HPFP) Failure:

Signs of failure:

Long crank time (slow engine start)
Check engine light illuminated
The car enters limp mode and runs poorly with decreased power


Probably the most severe and prevalent issue that crops up with the N54 is HPFP failure. Numerous reports back in 2010 caused a scandal for BMW in the U.S. and resulted in a class-action lawsuit. BMW announced a voluntary recall for 2007-2010 models mated with the N54 engine and even provided a ten year, 190,000km extended warranty for the HPFP. The recall affected 130,000 cars with nearly 40,000 BMW’s having their fuel-pump replaced. This only applies to the U.S unfortunately, but the upside is that BMW also introduced an updated design of its fuel injectors.

Why are the N54’s fuel-pumps failing and what’s the chance of you experiencing HFPF failure? No-one knows why some N54 engines are experiencing fuel-pump failures, and BMW has remained tightlipped. What we do know for sure is that BMW only issued recalls with models that had specific manufacturing codes, which would imply a “bad batch” from individual plants. Do a VIN check which will give you an accurate breakdown of your engine information - including the manufacturing plant. If you have a high mileage N54 or are looking to buy one, likely, the fuel pump has already been replaced at some point-in-time. Additionally, the chances of an HFPF failure is decreased further if you own or buy a post-2010 N54. If you find yourself hobbling along the highway, you’ve been dealt a bad hand, as the problem is entirely random and unavoidable.

Note: As mentioned earlier, the HFPF problem isn’t specific. Issues have been experienced by stock and tuned N54 engines and automatic and manual transmissions. Any performance part or tuning shouldn’t increase the chances of HFPF failure.

Repair/Replacement:

Unfortunately, it doesn’t get better after that. An HFPF failure would require a potentially costly replacement and can potentially lead to damage to other parts in the engine if left unchecked. The extended warranty is only applied in the U.S., so your options for recourse are limited. It's recommended to have a professional mechanic that's experienced with your car and can install the OEM HFPF for you, despite the additional cost it carries.

OEM Replacement Cost: Est. R8,000 (including labour).

2) Carbon Build-Up On The Intake Valves:

Symptoms of Carbon Build-Up:
The car is running “rough” while idling or stalling in cold conditions.
The car has more than 50,000km on the clock.

Another unavoidable but thankfully less problematic and less costly problem associated with the N54 and most direct fuel-injected engine cars, in general, is carbon deposit buildup on the intake valves. Direct injection, as opposed to port injection, engines spray the fuel directly into the combustion chamber rather than on the intake valves. Consequently, the detergents in petrol and the heat generated can't clean the valves which cause carbon buildup.

Repair/Replacement:

Cleaning carbon buildup from the valves is quite simple and some drivers, with some mechanical knowledge, do it themselves. However, its recommended that you have an experienced and qualified technician do it to avoid possible injury or damage to your car. Cleaning carbon build-up is usually done by:

Removing the intake manifold and removing the carbon with an abrasive medium.
Removing the cylinder heads and doing a valve job.
Chemical cleaning of the intake system.


Intake System Cleaning Cost: R3500

3) Wastegate/Turbocharger Failure:

Symptoms:

Wastegate rattle (rattling noise coming from engine).
Low boost engine codes.
A significant loss of power.
Smoke coming from exhaust (as a result of oil leaking from the turbo seals).

The most potentially expensive problem that seems to crop up on N54 engine forums frequently and has been noted in some reports is wastegate issues and turbo malfunctions. The wastegate controls the outflow of exhaust gases away from the turbocharger which regulates the speed of the turbo spool and levels of boost pressure. More importantly, the wastegate controls the maximum boost levels which protect your engine and turbochargers. The dreaded wastegate “rattle” is a direct result of the actuator/rod malfunctioning.

Repair/Replacement:

Wastegate issues and turbocharger failures are usually a result of simple wear and tear - like pushing your car or experimenting at higher boost levels. However, due to the disproportionate amount of drivers reporting turbocharger malfunctions, BMW issued an extended warranty (for U.S. drivers only) and updated the turbocharger system. If your turbo is still under warranty and you’re experiencing the rattle, take it to your dealer straight away. Usually, dealerships will update or adjust the ECU and tinker with the actuator arms, but that's a temporary fix. Make sure that you get them to replace the turbo before the warranty expires. Replacing a turbo out of warranty is expensive and labour intensive, but the sooner, the better.

OEM Replacement Cost:
Turbo replacement cost will be huge, it’s a lot of labour to remove the turbos

3) Water Pump Failure:

Symptoms:
Engine overheating, abnormal running temperatures
Water pump and fan running noise is very loud
Engine coolant draining abnormally fast
CEL Code 2E84


An issue that seems to extend to non-N54 engine BMW’s as well is water pump failure. Unfortunately, there isn’t a cheap and quick DIY fix you can do to the water pump as a failure would require a replacement.

Repair/Replacement:

The N54 water pump has been seen to last on average around 70,000km to 80,000km before needing a replacement. If you have high mileage or looking to buy a high mileage N54, the chances of the water pump being replaced already are quite high.

4) Valve Cover Oil Leak

Symptoms:
Oil can be seen on the threads of the spark plugs.
Oil can be seen on the ignition coils.
Crevices of the head/valve are filled with oil.
A distinct burning oil smell and possible smoke from the valve cover.
A low engine oil warning light.

Oil leaking from the valve cover and the valve gasket cover is another problem the N54 is prone to but usually as a result of wear and time. Gaskets are prone to degrading over time which can result in oil leaks and build up. The other issue is the valve cover cracking as a result of heat cycling between the engine block and cover.

Replacement/Repair:

If the oil leak is a result of a worn gasket, only the gasket would require changing - which is a simple DIY task. If your valve cover is cracked, it would require a replacement of both the valve cover gasket, which can be expensive.

OEM Replacement Cost:
Gasket:
Valve Cover and Gasket

5) Fuel Injector Issues:

Symptoms:
Difficulty cold-starting.
Misfiring on start.
Excess oil on spark plugs
Rough engine idling.

Fuel injector issues are usually associated with the HFPF problems mentioned above. Since BMW uses direct-injection as opposed to port-injection, there is a higher chance of carbon buildup which clogs the injectors.

Repair/Replacement:

As a consequence of carbon buildup, this results in a bad-spray pattern which results in the ignition plug getting too much or too little spray which causes rough idling and misfires. Thankfully, a clogged fuel injector is a quick job and replacements are relatively cheap.

Summary:

Some problems mentioned above are general and have been experienced by drivers across the ranges housing the N54 engine. If you’re experiencing an issue related to your N54 engine that hasn’t been mentioned, ask on our Q/A where our community members will be more than happy to help. Do you have N54 engine or are you looking to buy one? Are you worried that specific critical components haven’t been replaced or been replaced with OEM parts? Do a VIN check , which will you give up-to-date essential information about your car. Doing a VIN check is also the easiest stolen car check method!
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