BMW N53 engine problems: The N53 engine debuted in 2006 as an option in the facelifted BMW E60 5 Series. It was the successor to the very popular BMW N52 engine and was produced from 2006 to 2013. The BMW N53 engine followed BMW’s standard formula of naturally aspirated inline six-cylinder engines, upon which BMW built its legacy. The main difference from its predecessor, the N52 in-line six-cylinder, was the fact that the N53 is a direct-injection engine. At the same time, the N52 was still a “normal” engine with intake manifold injection (and to be honest, it was better). The N53 was manufactured exclusively in Germany and sold only in Europe.
Here are all the BMW N53 engine problems and reliability weak points that are known today, almost 10 years after this engine was phased out.
Which BMW models have the N53 engine?
- N53B25
2006-2010 BMW E60 & E61 523i 5-Series - N53B30 (150 kW)
2009-2011 F10 & F11 523i 5-Series - N53B30 (160 kW)
2007-2013 E90 & E91 & E92 & E93 325i 3-Series
2006-2010 E60 & E61 525i 5-Series - N53B30 (190 kW)
2009-2011 F10 & F11 528i 5-Series - N53B30 (200 kW)
2007-2010 E60 & E61 530i 5-Series
2007-2010 E63 630i 6-Series
2007-2013 E90 & E91 & E92 & E93 330i 3-Series
2011-2013 F10 530i 5-Series
BMW N53 Reliability
There is a lot to say about the reliability of the N53 engine, and unfortunately, there is not much positive. Most N53 problems are related to the replaceable parts of the engine. Here is the complete list of weak points and problems with the reliability of the N53:
Fuel injector problems
As mentioned earlier, the N53 engine was BMW’s first six-cylinder engine with direct injection. And with direct injection came a series of piezo injectors that were nothing but trouble, at least until 2014. This is the first of the most common BMW N53 engine problems. These injectors were known to fail, and many owners lost their hair because of the problems with the N53 injectors. The faulty injectors were known to leak fuel, flooding the cylinders with fuel, causing misfires, poor fuel efficiency, rough idling, and eventually lighting up the check engine light or even turning on limp mode to prevent further damage to engine parts. To further upset owners, BMW never issued an official recall for these faulty fuel injectors, but simply acquiesced.
We have already talked about piezo injectors, and while companies do offer remanufactured piezo injectors, they are not the best option (trust me, I bought them for my OM642 W211 Mercedes and was not happy with them). The best option in the case of the N53, and basically the only reliable option, is to buy post-2014 injectors that have fixed the problem of the previous injectors. Note that these injectors must be coded into the ECU so all injectors must have the same index!
If you buy a used car with the N53 engine, make sure that the injectors have been replaced with the latest 2014 version.
Coil pack problems
The N53 spark plugs usually need to be replaced once the faulty injectors cause the combustion chamber to overflow with fuel, resulting in spark plug damage. To fix the misfiring and rough idling, sometimes it is enough to replace the spark plugs. However, these engines have been known to have problems with faulty or inadequately working ignition coils. If the problems with rough idling and misfiring persist after the injectors and spark plugs have been replaced, it is clear that the ignition coils must also be replaced. Generally, the ignition coils on the N53 need to be replaced every 60,000 miles or 100,000 kilometers.
Spark plug problems
Yes, the N53’s problems seem to set off a chain reaction, as many of these vehicles have had problems with their fuel injectors and subsequently their spark plugs. The excessive amount of fuel leaking from the faulty piezo injectors causes the spark plugs to get dirty and wear out prematurely. A leaking valve cover gasket, as you would expect on a BMW, can also cause oil to leak from the spark plugs and in turn, destroy them prematurely. Common signs of bad spark plugs include misfiring, poor acceleration with stuttering, and a general loss of power and throttle response. Just like ignition coils, spark plugs need to be replaced at least every 60,000 miles or 100,000 kilometers.
High-pressure fuel pump problems.
Both the N53 6-cylinder naturally aspirated engine and the N54 6-cylinder turbocharged engine frequently suffered from HPFP (high-pressure fuel pump) failures. Since this problem was one of the apparent and extremely common BMW N53 engine problems, BMW issued an official recall for the affected vehicles.
Engines, where the high-pressure fuel pump failed, had a rough idle, took a long time to start, acceleration was jerky, and the half-engine check engine light came on as a warning on the dashboard. Because the high-pressure fuel pump failed, the engine was not getting the fuel it needed to operate properly. The lack of fuel caused the engine to crank longer than usual, the idle was unstable and rough, and the car felt rough under acceleration because the pump could not apply the necessary pressure to force fuel into the combustion chamber.
When the HPFP finally died, the engine simply stopped, and it could and did immediately, without warning. BMW later updated the design of the HPFP, which put an end to the terrible stories of random failures. If you want to buy a BMW with an N53 engine today, make sure the HPFP has been replaced with the updated version. If not, you are in for trouble.
Problems with gaskets and seals
As these vehicles age, you should expect to have to replace various gaskets around the engine. While this may seem like a trivial matter, the costs add up if you want to fully restore the engine to its original condition. An extremely small number of BMW owners with these engines also report head gasket failure, which is more challenging.
Problems with the NOx sensor
We do not quite understand why there is so little talk about this problem with the N53 engines, but NOx sensor failures are far more common than they should be or than they are with other engines. Failed NOx sensors also cause rough idling, misfiring in one or more cylinders, and engine stuttering. Basically, when the sensor fails, the engine does not know what the correct amount of fuel is at any given time. To find out which codes are listed in the diagnostic tools for a failed NOx sensor, check out this excellent guide from Bimmerprofs. Replacing the NOx sensor is relatively easy and many people do it themselves, but a new sensor will need to be coded, so it’s a good idea to hire a professional to do it. A new sensor costs about $ 400. It seems like many modern engines are plagued by NOx sensor issues, just like the W213 Mercedes E-Class, we reviewed a few days ago.
Low-pressure fuel sensor (29F3 error code)
As you can see in this E90post forum thread and many others like it, the N53 engine is notorious for displaying the 29F3 error code when scanning the vehicle with a diagnostic tool. Many owners get this error without the car actually having any problems, but in many cases, the fact that the error code shows up is a harbinger of future problems like poor idle and jerky acceleration.
The faulty part is the low-pressure fuel sensor and in rare cases, the low-pressure fuel pump. The low-pressure fuel sensor is not expensive, but replacing it is quite an ordeal. To replace it, the intake manifold must be removed. Many owners choose to also clean the intake manifold while removing it (apparently experienced BMW technicians can do this without removing the intake manifold, which is not what BMW specifies).
Engine Vanos problems
With the N53 engine, there are usually no problems with the Vanos unit. There are a few cases where high mileage vehicles need to have the Vanos solenoids replaced, but in general, a well-maintained vehicle with regular oil changes should not have these problems.
Noisy fuel lines
It seems like there is no end to BMW N53 engine problems but there is, don’t worry. This is just another strange problem, but it is more common than you would think. Many car owners report hearing fuel flowing through the fuel lines inside their vehicle from the rear tank to the front engine. There is no real solution other than turning the radio up louder and ignoring the noise.
Water Pump Problems
Like other 2006 and older model-year vehicles, the N53 engine is equipped with an electric water pump that has been known to fail without warning. If the vehicle you are considering buying has more than 80,000 miles or 140,000 kilometers on it and the water pump has not been replaced at least once in its life, you should expect the water pump to fail sooner or later.
Frequently asked questions
Is the BMW N53 engine reliable?
Yes, if all the typical problems are fixed (injectors, HPFP pump, water pump, spark plugs and ignition coils), the N53 engine is considered very reliable and does not have any major drawbacks that would shorten its life.
BMW N52 vs. N53 reliability?
There is no doubt that the older, much simpler N52 engine is more reliable. The N52 did not have problems with fuel injectors and high-pressure fuel pumps because it was still an intake manifold injection engine. The N53, on the other hand, is more fuel-efficient and has a more modern direct injection system.
Conclusion
Buying a car with an N53 engine is probably a better idea today than it was more than 10 years ago when it first came on the market. All of the common problems with these engines are now known and less expensive to fix. And again, if you are going to buy a BMW with this engine, make sure the above problems have been fixed. Despite all the BMW N53 engine problems we would still recommend this engine due to its efficiency and that amazing 6-cylinder sound we all love from BMW. Good luck!
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