The BMW S55 engine - a marvel in the automotive world, excels in delivering exhilarating performance, but like all machines, it's not without its share of issues. Understanding these common problems is crucial for any potential or current owner
BMW S55 Engine: An Overview
The BMW S55 engine, a powerhouse found in models like the M2, M3, and M4, is a testament to BMW's engineering prowess. Known for its impressive performance capabilities, the S55 is a force to be reckoned with in the automotive world. However, as with any high-performance engine, it comes with its own set of challenges. In this article, we delve into four common problems that S55 owners might encounter.
1. Crank Hub Issues
One of the most talked-about issues with the S55 engine is the crank hub problem. Contrary to popular belief, this isn't a widespread issue but rather a rare occurrence that has gained significant attention. The S55 shares its crank hub components with the N55 engine, and similar issues have been noted with the N54 as well. The problem typically manifests at high horsepower levels, particularly above 600 whp, which the S55 achieves more readily than its predecessors.
Symptoms of a Spun Crank Hub:
- Drivetrain malfunction light.
- Limp mode and rough idle.
- Engine fault codes.
It's important to note that a spun crank hub can suddenly disrupt engine timing, necessitating a replacement and timing correction. In rare cases, continued operation with a spun hub can lead to more severe engine damage.
2. Valve Cover & Gasket Oil Leaks
A common ailment in modern BMW engines, including the N54 and N55, the S55 is not immune to valve cover and gasket oil leaks. Over time and under the stress of high temperatures, the rubber gasket can crack, leading to leaks. The S55's plastic valve covers are also prone to cracking, although less frequently than gasket failures. These leaks often start manifesting before the engine reaches 60,000 miles.
Symptoms of Valve Cover Gasket Leaks:
- Low engine oil light.
- Burning oil smells.
- Smoke from the valve cover area.
- Oil on spark plug threads.
3. Oil Pan Gasket Leaks
The S55's oil pan gasket, another component it shares with the N55, is susceptible to degradation and cracking over time. While not as common as other leaks, its location makes repairs labor-intensive, as it requires dropping the sub-frame. It's a wise preventive measure to replace the gasket whenever the sub-frame is removed for other maintenance.
Symptoms of Oil Pan Gasket Leaks:
- Lower engine oil levels.
- Oil stains on the ground or under-body shield.
4. Oil Filter Housing Gasket Leaks
Again, a shared component with the N54 and N55, the S55's oil filter housing and gasket are prone to leaking as they age. This can lead to oil dripping onto the belt, which may cause the belt to fail or slip, potentially leading to further engine damage. It's common for these leaks to begin appearing around the 50,000-mile mark.
Symptoms of Oil Filter Housing Gasket Leaks:- There are visible oil leaks around the oil filter housing area.
- Oil is present on the drive belt.
- Frequent low-oil warnings.
BMW S55 Reliability
Despite these issues, the BMW S55 remains an exceptional engine known for its robust performance. Most of the problems listed are associated with aging components, typical in high-performance engines. The good news is that these are mostly manageable with regular maintenance and timely repairs.
As the S55 engines continue to age, it’s wise for owners and potential buyers to be aware of these issues. However, it's important to remember that these problems are not unique to the S55 and are often seen in similar high-performance engines. With proper care and maintenance, the S55 can be a reliable and exhilarating powertrain.
In conclusion, while the BMW S55 engine may have its common issues, its performance and capabilities far outweigh these drawbacks. As with any vehicle, awareness and maintenance are key to enjoying the thrilling experience that an S55-powered BMW offers.
