What should be done if a lubricant shows signs of overheating?

When a lubricant shows signs of overheating, replacing it and investigating the cause is the most appropriate action. Overheating can lead to the breakdown of the lubricant's properties, resulting in reduced effectiveness and potentially causing damage to the machinery it is meant to protect. By replacing the overheated lubricant, you ensure that the machinery is once again operating with a substance that maintains proper viscosity, lubrication, and protective qualities.

Moreover, investigating the cause of overheating is crucial for preventing future occurrences. Factors contributing to overheating can include excessive load, lack of adequate ventilation, or malfunctioning equipment. Identifying and addressing these issues can help maintain optimum operational performance and extend the life of both the lubricant and the machinery.

The other options do not adequately address the risks and potential damage associated with overheating. For instance, leaving the lubricant as it is would only exacerbate any existing problems and could lead to serious machinery failure. Mixing lubricants can create incompatible substances that may not perform effectively together, posing further risks. Simply adding more lubricant does not resolve the underlying overheating issue and can lead to further contamination and efficiency problems. Therefore, replacing the lubricant and thoroughly investigating the cause is essential for effective machinery maintenance.