The computer was overheating and began making a noise.
The repair went excellently. To be honest this wasn't the first time I had had to perform surgery on this Macbook. A few years ago I had replaced the hard drive so I was already familiar with disassembling the computer and had the correct tools.
The only thing that I had any problem with was disconnecting and reconnecting the photo sensor. I wasn't real familiar with the type of connector and the thing is almost microscopic so it's hard to see how it worked. Once I understood how the connector worked I had no problem.