Dealing with the oil leakage problem at the end cover of the bearing box of a large mixed flow pump requires multiple aspects, including checking and replacing oil seals, using sealants or leak-stopping agents, strengthening sealing measures, checking and adjusting installation, ensuring the vent is unobstructed, and paying attention to other related matters. In actual operation, you should choose the appropriate treatment method according to the specific situation. If the problem is serious or cannot be solved by yourself, you should seek help from professional technicians.