Freezer makes loud knocking or banging noises during compressor start or stop.

Safety first: Unplug the freezer before working near the compressor or metal tubing.

Step-by-step checks:

• 1. Access rear compartment: Remove the rear cover to expose the compressor and tubing.
• 2. Check mounts: Ensure the compressor mounting bolts are snug but not overtightened. Replace cracked rubber mounts.
• 3. Isolate tubing: Look for copper lines touching each other or the cabinet. Gently bend them apart a few millimeters and insert foam or rubber spacers to prevent contact.
• 4. Evaluate noise: If knocking persists and seems to come from inside the compressor, it may be internal wear. The unit can sometimes continue to operate, but eventual compressor replacement by a technician may be required.