2018 BMW 420i Gran Coupe

The 2018 BMW 420i Gran Coupe is a stylish and practical four-door coupe that blends sporty handling with everyday usability. The model we’ll focus on is equipped with the 2.0-liter turbocharged four-cylinder engine, producing 180 horsepower and 200 lb-ft of torque. Other engine options for the 2018 4 Series Gran Coupe include the more powerful 430i with a 248hp 2.0L turbo 4 cylinder and the 440i with a 320hp 3.0L turbo inline-6. All engines were offered with either an 8-speed automatic transmission or a 6-speed manual (though the manual is far less common). Drivers often praise the 420i Gran Coupe for its sleek design, comfortable interior, and engaging driving dynamics, but some find the rear passenger space limited and the base engine slightly underpowered.

Engine

2.0L Turbocharged Four-Cylinder (B48)

• Timing Chain Issues
  • Description/Symptoms: Some owners have reported issues with the timing chain stretching or failing prematurely. Symptoms include a rattling noise from the engine, especially on startup, and potential engine misfires or failure to start.
  • Solution: Replacement of the timing chain, tensioner, and associated components is required.
  • Estimated Cost to Fix: $1,500 - $3,000+
  • Recalls: None Found
• Oil Leaks
  • Description/Symptoms: Oil leaks from various locations, including the valve cover gasket, oil filter housing gasket, and rear main seal. These leaks can lead to low oil levels, engine damage, and oil spots on the driveway.
  • Solution: Replacement of the leaking gaskets or seals is necessary.
  • Estimated Cost to Fix: $200 - $1,000+ depending on the location of the leak.
  • Recalls: None Found

Transmission

8-Speed Automatic (ZF 8HP)

• Rough Shifting
  • Description/Symptoms: Some owners have experienced rough or delayed shifting, particularly between certain gears. This can be more noticeable when the transmission is cold.
  • Solution: In some cases, a software update can improve shifting performance. If the problem persists, valve body replacement or a full transmission rebuild may be necessary.
  • Estimated Cost to Fix: $150 (software update) - $4,000+ (transmission rebuild).
  • Recalls: None Found

Suspension

• No Issues Found

Electrical

• iDrive System Malfunctions
  • Description/Symptoms: The iDrive infotainment system can experience various glitches, including freezing, rebooting, and display issues.
  • Solution: A software update is often the first step in addressing iDrive problems. In some cases, the iDrive controller or head unit may need to be replaced.
  • Estimated Cost to Fix: $150 (software update) - $1,500+ (component replacement).
  • Recalls: None Found
• Battery Drain
  • Description/Symptoms: Some owners have reported excessive battery drain, leading to difficulty starting the car or a dead battery.
  • Solution: Diagnosis is required to identify the source of the drain, which could be a faulty module, a parasitic draw, or a failing battery.
  • Estimated Cost to Fix: $100 - $500+ depending on the cause.
  • Recalls: None Found

Exterior

• Door Handle Issues
  • Description/Symptoms: Some owners have reported issues with the comfort access feature, causing the door handle to fail to open or close properly.
  • Solution: Replacement of the door handle.
  • Estimated Cost to Fix: $300 - $800+
  • Recalls: None Found

Interior

• Sunroof Issues
  • Description/Symptoms: Owners have had issues with their sunroofs not opening and closing properly. Some have also reported excessive noise, like clicking.
  • Solution: In some cases, the tracks of the sunroof will need to be lubricated. If the issues persist, then the sunroof motor and other parts may need to be replaced.
  • Estimated Cost to Fix: $500 - $1,500+
  • Recalls: None Found

Summary

The 2018 BMW 420i Gran Coupe is generally a reliable vehicle, but owners should be aware of potential issues, particularly with the timing chain, oil leaks, iDrive system, and sunroof. The severity and cost of these issues can vary, but addressing them promptly can help prevent more significant problems down the road. While some issues are relatively inexpensive to fix, others, such as timing chain replacement or transmission rebuilds, can be costly.