2008 BMW 335xi
2008 BMW 335xi
Overview
The 2008 BMW 335xi, a performance-oriented all-wheel-drive sedan, offers a compelling blend of luxury, power, and handling. Powered by potent turbocharged inline-six engines and paired with sophisticated transmissions, it aims to deliver an engaging driving experience. However, like many high-performance vehicles of its era, it is not without its potential reliability concerns, particularly related to its complex powertrain and electronic systems. Owners should be aware of common issues that can arise, impacting both performance and long-term ownership costs. This analysis focuses on documented, non-wear-and-tear related problems.
Engine
3.0L Twin-Turbocharged Inline-6 (N54)
High-Pressure Fuel Pump (HPFP) Failure
- Symptoms: Stalling, rough idle, engine misfires, check engine light, difficulty starting.
- Solution: Replacement of the fuel pump.
- Cost: $800 - $1500
Turbocharger Wastegate Rattle
- Symptoms: Rattling noise from the engine bay, especially on cold starts or at low RPMs.
- Solution: Replacement of wastegate actuators or turbochargers.
- Cost: $1500 - $3000+
Fuel Injector Failure
- Symptoms: Misfires, rough running, check engine light, poor performance.
- Solution: Replacement of faulty fuel injectors.
- Cost: $300 - $600 per injector
PCV Valve Failure
- Symptoms: Oil leaks, rough idle, increased oil consumption, blue smoke from exhaust.
- Solution: Replacement of the PCV valve assembly.
- Cost: $300 - $600
Transmission
6-Speed Automatic (GM GA6HP19Z)
Mechatronic Unit Failure
- Symptoms: Harsh shifting, transmission slipping, failure to engage gears, transmission warning light.
- Solution: Repair or replacement of the mechatronic unit.
- Cost: $1500 - $3000
Torque Converter Issues
- Symptoms: Shuddering at low speeds, slipping, delayed engagement.
- Solution: Replacement of the torque converter.
- Cost: $1000 - $2000
6-Speed Manual
No widespread issues reported.
- Symptoms: N/A
- Solution: N/A
- Cost: Varies
Suspension
Standard Chassis
No widespread issues reported.
- Symptoms: N/A
- Solution: N/A
- Cost: Varies
Electrical
General Electrical System
Water Pump Failure (Electric)
- Symptoms: Overheating, coolant leaks, check engine light.
- Solution: Replacement of the electric water pump and thermostat.
- Cost: $700 - $1200
Idiot Lights / Warning Lights
- Symptoms: Various warning lights illuminating on the dashboard without clear cause, often related to sensor issues.
- Solution: Diagnosis and replacement of faulty sensors (e.g., ABS, DSC, tire pressure).
- Cost: $200 - $800 per sensor
Exterior
Body and Trim
No widespread issues reported.
- Symptoms: N/A
- Solution: N/A
- Cost: Varies
Interior
Cabin Electronics and Features
iDrive System Glitches
- Symptoms: Freezing, unresponsiveness, error messages on the infotainment screen.
- Solution: Software updates or replacement of the iDrive controller/head unit.
- Cost: $500 - $1500
Sunroof Drain Clogs
- Symptoms: Water leaks into the cabin, particularly in the footwells or headliner, mold/mildew smell.
- Solution: Clearing of sunroof drains and potentially drying/repairing interior water damage.
- Cost: $200 - $500
Summary Verdict
The 2008 BMW 335xi offers exhilarating performance but requires diligent maintenance and awareness of its specific potential failure points. The N54 engine, while powerful, is prone to issues with its high-pressure fuel system, turbos, and injectors, which can be costly to repair. Automatic transmission issues, particularly with the mechatronic unit, are also a concern. Electrical gremlins, such as water pump failures and various sensor issues, can also arise. While the manual transmission and suspension are generally more robust, owners should budget for potential powertrain and electrical repairs to maintain this performance luxury vehicle.