2009 BMW 135i

The 2009 BMW 135i is a compact performance coupe/convertible known for its engaging driving dynamics and potent engine. The main engine option for this model year is the N54 3.0-liter twin-turbo inline-six, producing 300 horsepower and 300 lb-ft of torque. A less common engine option is the naturally aspirated 3.0-liter inline-six N52 engine. Transmission options include a 6-speed manual and a 6-speed automatic. Owners often praise the 135i for its responsive handling, powerful engine, and relatively compact size. However, common complaints revolve around reliability issues, particularly with the N54 engine’s high-pressure fuel pump and turbocharger system.

Engine

N54 3.0L Twin-Turbo Inline-Six

• High-Pressure Fuel Pump (HPFP) Failure
  • Description/Symptoms: Long crank times, rough idle, hesitation during acceleration, and eventual engine stalling. Can trigger a check engine light.
  • Solution: Replacement of the HPFP. Several revisions of the HPFP exist, with later versions being more reliable.
  • Estimated Cost to Fix: $800 - $1200+
  • Recalls: None Found
• Turbocharger Wastegate Rattle
  • Description/Symptoms: Rattling noise from the rear of the engine, especially during cold starts or low RPMs. This is caused by excessive play in the turbocharger wastegate actuator rods.
  • Solution: Replacement of the turbochargers. Some have had success with aftermarket wastegate actuator rod clips to reduce the rattle.
  • Estimated Cost to Fix: $3000+ (for turbocharger replacement)
  • Recalls: None Found
• Fuel Injector Failure
  • Description/Symptoms: Rough idle, misfires, and reduced performance. Often accompanied by a check engine light.
  • Solution: Replacement of faulty fuel injectors. It’s generally recommended to replace all injectors at the same time for consistent performance.
  • Estimated Cost to Fix: $1200 - $2000+
  • Recalls: None Found
• Oil Leaks (Valve Cover Gasket, Oil Filter Housing Gasket)
  • Description/Symptoms: Visible oil leaks on the engine, burning oil smell, and low oil level.
  • Solution: Replacement of the affected gaskets.
  • Estimated Cost to Fix: Valve Cover Gasket: $400 - $800+, Oil Filter Housing Gasket: $300 - $600+
  • Recalls: None Found
• Carbon Buildup on Intake Valves
  • Description/Symptoms: Rough idle, hesitation during acceleration, and reduced power. This is a common issue with direct-injection engines.
  • Solution: Walnut blasting or chemical cleaning of the intake valves.
  • Estimated Cost to Fix: $400 - $800+
  • Recalls: None Found

N52 3.0L Naturally Aspirated Inline-Six

• Valve Cover Gasket Oil Leak
  • Description/Symptoms: Visible oil leaks on the engine, burning oil smell, and low oil level.
  • Solution: Replacement of the valve cover gasket.
  • Estimated Cost to Fix: $400 - $800+
  • Recalls: None Found

Transmission

6-Speed Manual

• Clutch Failure
  • Description/Symptoms: Clutch slippage, difficulty shifting, and a burning smell.
  • Solution: Clutch replacement.
  • Estimated Cost to Fix: $1200 - $2000+
  • Recalls: None Found
• Shifter Bushing Wear
  • Description/Symptoms: Increased sloppiness and free play in the shifter.
  • Solution: Replacement of worn shifter bushings.
  • Estimated Cost to Fix: $200 - $400
  • Recalls: None Found

6-Speed Automatic

No Issues Found

Suspension

• Cracked Front Control Arm Bushings
  • Description/Symptoms: Clunking noise from the front suspension, especially over bumps. Can also cause vague steering and uneven tire wear.
  • Solution: Replacement of the front control arm bushings or the entire control arm assembly.
  • Estimated Cost to Fix: $400 - $800+
  • Recalls: None Found

Electrical

• Battery Drain
  • Description/Symptoms: Car battery drains overnight or within a few days of non-use.
  • Solution: Diagnose and repair the source of the parasitic drain. Common culprits include faulty sensors, aftermarket accessories, or a failing electronic module.
  • Estimated Cost to Fix: $100 - $1000+ (depending on the source of the drain)
  • Recalls: None Found
• Comfort Access Issues
  • Description/Symptoms: Intermittent or complete failure of the Comfort Access system, which allows keyless entry and starting.
  • Solution: Diagnose and replace faulty door handle sensors or key fobs.
  • Estimated Cost to Fix: $300 - $800+
  • Recalls: None Found

Exterior

• Rust on Rear Subframe
  • Description/Symptoms: Visible rust forming on the rear subframe.
  • Solution: Replacement of the rear subframe or rust repair.
  • Estimated Cost to Fix: $1000 - $3000+
  • Recalls: None Found

Interior

• Broken or Stuck Sunroof
  • Description/Symptoms: Sunroof doesn’t open or close correctly.
  • Solution: Repair or replacement of damaged sunroof motor, cables, or tracks.
  • Estimated Cost to Fix: $500 - $1500+
  • Recalls: None Found

Summary

The 2009 BMW 135i, particularly those equipped with the N54 engine, can be a rewarding but potentially costly car to own. The most prevalent issues revolve around the N54 engine’s fuel and turbocharger systems. While the HPFP issue may have been addressed under warranty or recall in some cases, turbocharger wastegate rattle, carbon buildup, and oil leaks remain common concerns. Suspension issues are also typical for a car of this age, and electrical problems can arise. Repair costs can range from a few hundred dollars for minor fixes to several thousand for major engine or transmission work. Prospective buyers should thoroughly inspect the car’s maintenance history and be prepared for potential maintenance expenses.