my BMW 3 Series makes a knocking noise when accelerating what's wrong

Solution

1. Preparation

• Gather tools and parts required for inspection and repair.
• Disconnect the negative battery terminal to ensure safety.

2. Inspect Engine Mounts

• Remove any components obstructing access to the engine mounts (if necessary).
• Visually inspect the engine mounts for cracks or deterioration.
• Use a pry bar to check for excessive movement in the mounts.
• Replace any damaged mounts with OEM parts. Torque to manufacturer specifications.

3. Check Transmission Fluid

• Locate the transmission dipstick, remove it, and wipe it clean.
• Reinsert the dipstick and check the fluid level; add fluid if low.
• Inspect fluid for a burnt smell or dark color, which indicates it may need replacement.
• If necessary, perform a fluid change and replace the transmission filter.

4. Inspect Exhaust System

• Visually check the exhaust system for any loose or damaged components.
• Tighten any loose bolts or clamps, and replace any damaged sections of the exhaust.
• Use a rubber mallet to check for rattling sounds in the exhaust system.

5. Check Suspension Components

• Raise the vehicle and support it securely on jack stands.
• Inspect the struts, control arms, and bushings for wear and damage.
• Replace any worn or damaged components with OEM parts.
• Reassemble all components and torque bolts to specifications.