Guardian opener is very noisy during operation, with grinding or rattling sounds.

Safety first: Disconnect power before tightening hardware or lubricating. Do not place hands near moving parts when testing.

• Tighten hardware: Check all opener mounting bolts, rail joints, and header bracket bolts. Tighten as needed.
• Lubricate chain and door: Lightly lubricate the chain (if chain drive) and all door hinges and rollers with garage-door lubricant. Do not over-lubricate the belt on belt-drive models.
• Inspect sprockets and pulleys: Look for wobbling or worn teeth on the drive sprocket and idler pulley. Replace if noisy or worn.
• Check rail alignment: Ensure the rail is straight and not flexing excessively during operation.