why does my BMW 3 Series F30/F31 (2012-2019) have excessive vibration when idling?

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Ensure the vehicle is parked on a flat surface and the engine is turned off.
• Disconnect the battery to prevent electrical issues.

2. Inspect and Replace Engine Mounts

• Tools Required: Socket set, torque wrench, pry bar.
• Sub-steps:
  1. Raise the vehicle securely on jack stands and remove the front underbody cover if applicable.
  2. Locate the engine mounts; these are typically positioned between the engine and the chassis.
  3. Use a pry bar to gently lift the engine slightly for access.
  4. Remove the bolts securing the engine mounts using a socket set.
  5. Replace the damaged mounts with new ones, ensuring they are aligned properly.
  6. Torque the bolts to the manufacturer's specifications (usually around 30-50 Nm).
  7. Lower the engine and recheck the alignment.

3. Inspect and Replace Spark Plugs and Ignition Coils

• Tools Required: Socket set, torque wrench, spark plug gap tool.
• Sub-steps:
  1. Remove the engine cover to access the spark plugs and ignition coils.
  2. Disconnect the electrical connectors from the ignition coils.
  3. Remove the ignition coils using a socket set.
  4. Inspect the spark plugs for wear; replace if necessary with new OEM-spec plugs, ensuring the gap is set correctly.
  5. Install new ignition coils and reconnect electrical connectors.
  6. Reattach the engine cover.

4. Address Vacuum Leaks

• Tools Required: Smoke machine (if available) or listen for leaks.
• Sub-steps:
  1. Start the engine and listen for any hissing sounds that indicate a vacuum leak.
  2. If available, use a smoke machine to introduce smoke into the intake system and watch for smoke escaping from the intake manifold or hoses.
  3. Replace any damaged vacuum hoses or seals as needed.