The BMW N55 inline-six engine debuted in 2006 as an upgrade from its predecessor, the N54. Equipped with Valvetronic and VANOS technologies, it stands out for its power and BMW N55 reliability.
As with any engine, this one can be customized to produce impressive power on the dyno. However, like all engines it does have some issues that need to be addressed.
Cracked plastic charge pipes may crack over time due to heat cycles. Furthermore, oil leakage from water pumps or filter housing gaskets is commonplace.
Enter the N55, bringing with it a far more reliable BMW engine capable of supporting upgrades and modifications. Its single twin-scroll turbo design eliminated many of the misfires and exhaust pullback issues encountered with its predecessor – plus allowed higher boost levels without running into turbo lag issues.
Furthermore, its use of forged crankshaft technology prevented cracking that the N54’s cast unit had experienced due to temperature extremes.
In its stock form, the N55 produces plenty of horsepower and has what many consider to be an ideal inline six engine sound. Unfortunately, however, it does have its quirks; most frequently its plastic intake manifold which degrades over time on high power applications; VRSF offers replacement kits which make an investment worthwhile over time.
The BMW N55 introduced Valvetronic, an adjustable valve lift system which remains used across multiple engines today and which formed the basis for high-performance versions like S55.
Here are some common failures that we should consider about BMW N55 reliability:
Cracked Charge Pipe
In some cases, drivers may face a cracked charge pipe. This should be counted among issues related to BMW N55 reliability. Plastic charge pipes can become vulnerable over time with heat cycles and boost pressure, cracking under constant strain and ultimately leading to loss of boost and limp mode states. Installing a metal charge pipe as an upgrade could significantly boost boost levels on tuned cars.
ARM N55 aluminum charge pipe is built for long-term use, featuring a durable black powdercoat wrinkle finish and CNC machined flange. Additionally, this piece comes equipped with an o-ring and c-clip to keep it securely connected to the throttle body, and includes a 1/8″ NPT bung for injecting methanol or monitoring boost gauges.
VANOS solenoids on BMW N55 engines are responsible for adjusting cam gear timing, but over time these solenoids can wear down and stop functioning, leading to issues like rough idle, low RPM bucking, and the Check Engine Light illumination due to lean conditions.
The N55, like its predecessor the N54, is susceptible to oil leakage issues. This is often due to wear on its valve cover and gasket that weep oil over time due to constant exposure to high heat. Over time this could affect accessory belts as well and if any oil escapes it may enter into your engine and cause severe damage.
In some cases such as long term usages, you can experience oil leaks failure due to BMW N55 reliability.
An additional issue plaguing the N55 is its timing chain, which may stretch or even break over time due to exposure from engine and transmission components. A broken timing chain could result in rough running conditions and misfires; for this reason it should be inspected regularly for signs of trouble.
Overall, the BMW N55 engine is an extremely dependable one with plenty of tuning potential for those willing to push it to its limit. However, it is important to remain aware of four common issues with this engine so as to stay safe and enjoy driving for as long as possible.
Water Pump Failure
The BMW N55 engine is an efficient, dependable power plant found in many of their top vehicles; however, it may contain hidden problems that require you to be aware of prior to making a decision on purchasing it. As an owner or prospective buyer it is crucially important that you are informed about any possible issues related to its operation before committing.
One of the more frequent issues associated with an N55 is a leaking valve cover gasket. Over time, its rubber gasket can degrade due to high engine temperatures, leading to oil leaking down onto other engine components and hastening their wear down prematurely.
Another source of leakage can be the oil filter housing gasket, a common issue among BMWs that utilize this engine. Over time, rubber gaskets may break down and start leaking oil around the filter housing and spill onto drive belts causing them to wear down or even snap over time.
Finally, the N55 electric water pump has a limited lifespan and could break at any moment, leading to reduced coolant flow that overheats and damages its engine. Preventative maintenance should always be practiced so as to ensure this does not happen again; replacing the pump may be the answer to all future engine troubles.
Oil Filter Housing Gasket Leak
BMW engines have long been revered for their remarkable BMW N55 reliability, but even the most efficient engines may experience issues from time to time. BMW introduced their N55 engine as a replacement to the N54 in 2009 and it quickly earned rave reviews among drivers for being powerful yet reliable and offering plenty of tuning potential – many consider it an improvement over its predecessor.
One issue drivers are experiencing with the N55 is an oil filter housing gasket leak. The oil filter housing, located on the front of the engine and connected to its cylinder head with a rubber gasket, seals its connection and prevents oil leaking into the coolant hose that runs beneath. Unfortunately, due to high engine temperatures and soft material composition of its materials used for construction, its seal may fail over time and leak into coolant lines running underneath the engine.
Good news – the N55 oil filter housing gasket replacement is relatively affordable at under $20 and installation should not take long. Replacing it quickly could save hundreds in labor costs in the future should an undiagnosed leak go undetected for too long; additionally it would be wise to change out both water pumps at this time as they tend to become problematic on most BMW models.