Yes, a similar thing happened to me. To be fair, it might be that you do need a new logic board, but I would recommend that you start with a good cleaning first.
My wife used to have a 12" powerbook G4 that she would use in the kitchen. One day she managed to put it down in something that was a mixture of some sauce with flour. This clogged up the air vents in a certain spot almost completely.
She didn't tell me this happened, and so I started with troubleshooting the same issues that you describe. It would overheat and shut off, have racing fans etc. Sometimes other random crashes and stuff or weird behavior.
When I discovered the real problem I sat down with some sharp tools and dug all the crap out of the vents, and what do you know? It worked great after that! Just like new.
Start with that, which might mean no take apart needed at all. If that doesn't help, then use the iFixit takeapart guide for your model to see how to take the case off enough to get to the fans.
http://www.ifixit.com/Guide/Repair/Installing-PowerBook-G4-Aluminum-17-Inch-1-1-67-GHz-Heat-Sink-Fan-Assembly/259/1