Why is my power adapter overheating

@bilalimwenda that can be caused by a bad battery. Replace the battery then re-evaluate. If it continues to overheat, replace the charging board. Anything after that will require a boardlevel repair. For that you will need to have the schematic the boardview files and will have to know how to repair board level components.

Since iFixit does not yet have a specific guide for that use this video or use the instructions from here Batteries and charging boards are readily available at many online stores.

While you work on your phone, take lots of pictures. Once you are done with it, take those pictures and create a guide for iFixit. That will help the next person that has a device with the same issues as you do. It's easy and fun to create these guides. https://ifixit.com/Guide/new The iFixit community will appreciate this.

Repair is War on Entropy!