why does my BMW 3 Series F30/F31 (2012-2019) make a knocking noise when starting

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a flat surface and the engine is cool.
• Disconnect the battery to ensure safety during repairs.

2. Check Engine Oil

• Remove the dipstick and wipe it clean.
• Reinsert the dipstick and remove it again to check oil level; add oil if necessary.
• If oil is dirty, perform an oil change.
  • Tools Required: Oil filter wrench, socket set, oil catch pan.
  • Oil Type: Refer to owner’s manual for recommended oil specifications.

3. Inspect and Replace Engine Mounts (if required)

• Raise the vehicle and secure with jack stands.
• Remove any components obstructing access to engine mounts.
• Use a socket set to unbolt the engine mounts from the engine and frame.
• Replace with new engine mounts and torque to manufacturer specifications (refer to repair manual).
• Reassemble any components previously removed.

4. Check Timing Components

• Remove the timing cover using a socket set.
• Inspect the timing chain/belt for wear, tensioner function, and alignment.
• Replace any worn components following manufacturer guidelines.
  • Tools Required: Torque wrench, timing tool set (if applicable).