The BMW 135i, a performance-oriented subcompact car, offered a thrilling driving experience and a unique blend of practicality and power. Understanding the nuances of each model year is crucial for potential buyers looking for the most reliable and enjoyable ownership experience. This guide delves into the best (and worst) years of the BMW 135i, highlighting key features, common problems, and overall reliability.
BMW 135i Model Year Comparison
| Model Year | Strengths | Potential Issues |
|---|---|---|
| 2008 | First year of the 135i, iconic N54 engine (twin-turbo), hydraulic steering feel. | N54 engine prone to high-pressure fuel pump (HPFP) failure, injector issues, wastegate rattle, oil leaks. Early iDrive system is less advanced. |
| 2009 | Minor improvements over 2008, N54 engine. | Same N54 engine issues as 2008, potential for HPFP failure, injector issues, wastegate rattle, oil leaks. |
| 2010 | N54 engine, some minor updates to interior trim. | Continued N54 engine issues, though some components may have been updated. HPFP, injectors, wastegate rattle, oil leaks remain a concern. |
| 2011 | Introduction of the N55 single twin-scroll turbo engine (from mid-year), improved fuel efficiency. | N55 engine is generally more reliable than the N54 but can still suffer from oil leaks and occasionally valvetronic issues. |
| 2012 | N55 engine, updated iDrive system. | N55 engine issues, though less frequent than N54. Oil leaks, potential for water pump failure. |
| 2013 | Final year of the 135i coupe and convertible. N55 engine. | N55 engine issues, possibility of higher mileage cars needing more maintenance. |
Detailed Explanations
2008: The inaugural year of the 135i, the 2008 model is beloved for its raw driving experience and the potent N54 twin-turbo engine. Its hydraulic steering provides exceptional feedback, a feature often missed in newer models. However, the N54 engine is known for its issues like high-pressure fuel pump (HPFP) failures, injector problems, wastegate rattle, and oil leaks. The early iDrive system is also less user-friendly compared to later iterations.
2009: The 2009 135i is largely similar to the 2008 model, retaining the N54 engine and its associated benefits and drawbacks. While there might be minor refinements, the core mechanical components remain the same. This means the potential for HPFP failures, injector issues, wastegate rattle, and oil leaks persists.
2010: The 2010 model year continues with the N54 engine, and while BMW likely addressed some of the initial issues, the fundamental problems remain. Potential buyers should still be aware of the possibility of HPFP failure, injector problems, wastegate rattle, and oil leaks. Thorough pre-purchase inspections are essential.
2011: A significant turning point for the 135i, 2011 saw the introduction of the N55 single twin-scroll turbo engine mid-year. This engine offered improved fuel efficiency and, generally, greater reliability compared to the N54. While still susceptible to some issues like oil leaks and occasional valvetronic problems, the N55 is considered a more robust option. Identifying whether a 2011 model has the N54 or N55 is crucial.
2012: The 2012 135i is equipped with the N55 engine and features an updated iDrive system, offering a more modern user experience. While the N55 engine is more reliable than the N54, potential buyers should still be mindful of potential oil leaks and the possibility of water pump failure.
2013: The final year of the 135i coupe and convertible, the 2013 model uses the N55 engine. While the engine is generally reliable, these vehicles are now older and may require more maintenance due to higher mileage and age. A comprehensive inspection is highly recommended before purchase.
Frequently Asked Questions
Which BMW 135i engine is more reliable, the N54 or N55? The N55 engine is generally considered more reliable than the N54 due to its simpler design and fewer common failure points.
What are the most common problems with the N54 engine? The most common problems with the N54 engine include high-pressure fuel pump (HPFP) failure, injector issues, wastegate rattle, and oil leaks.
What should I look for when buying a used BMW 135i? Look for service records, check for oil leaks, listen for unusual engine noises (like wastegate rattle), and have a pre-purchase inspection performed by a qualified BMW mechanic.
Is the BMW 135i expensive to maintain? Yes, the BMW 135i can be relatively expensive to maintain, especially models with the N54 engine due to their higher potential for mechanical issues.
Are the 135i coupes and convertibles the same mechanically? Yes, the coupes and convertibles share the same engines, transmissions, and basic mechanical components. The primary difference is the body style.
Does the 135i have any common electrical issues? While not as prevalent as mechanical issues, some 135i models can experience electrical problems, particularly with sensors and the iDrive system.
What is the best year 135i to buy? A 2012 or 2013 model with the N55 engine is generally considered the best choice due to its improved reliability and updated iDrive system.
How can I tell if a 2011 135i has an N54 or N55 engine? The easiest way is to check the engine cover. The N54 has a twin-turbo design with visible turbochargers, while the N55 has a single twin-scroll turbo and a different engine cover design. You can also check the VIN with a BMW dealer.
What is wastegate rattle? Wastegate rattle is a rattling noise that comes from the turbochargers when the wastegates are loose or worn. It's a common issue on the N54 engine and often requires turbocharger replacement or repair.
Are there any aftermarket solutions to the N54's HPFP issue? Yes, there are aftermarket HPFP upgrades that are often more reliable than the original BMW part.
Conclusion
Choosing the right year of BMW 135i is critical for a positive ownership experience. While the early models (2008-2010) with the N54 engine offer a raw and exciting driving experience, they are also prone to more frequent and costly repairs. The later models (2011-2013) with the N55 engine provide a better balance of performance and reliability. Therefore, a 2012 or 2013 model is generally recommended.