Which symptoms can indicate a faulty transformer?

The symptoms indicating a faulty transformer include unusual noises, discoloration, leaking fluid, or unusual heat. Unusual noises can be a sign of internal faults or mechanical wear within the transformer, which may produce sounds like humming or buzzing. Discoloration, particularly on the transformer exterior, may indicate overheating or insulation breakdown, which can compromise the unit's functionality. Leaking fluid typically suggests a failure in the insulation or seals, leading to the escape of insulating oil, which is critical for the transformer's operation and cooling. Unusual heat may suggest overheating, often resulting from internal short circuits or overloads. Collectively, these symptoms present a clear indication that a transformer may be experiencing significant issues that could lead to its failure or pose safety hazards.