My car has been over heating recently, so I went to a friend of a friend to see if I could just get a diagnosis, and he noticed my check engine light was on, so when he checked it out he said my camshaft actuator was bad.

He briefly explained why this was bad (cause hell if I know) and mentioned it has to do with the cars timing? the car thinks I'm going much faster than I am, so the motor is going, making it really hot, and on top of that my fan isn't kicking in on it's own so he mentioned to run the AC so that it does kick in. I didn't get an answer as to why the fan isn't working but he said I really needed to worry about the camshaft first and foremost.

He also wasn't sure if that was something I could buy aftermarket or if I had to go through GM. He said if I got the part, we'll talk cost of installing it and that it shouldn't be much of an issue to get to.

Any thoughts, insight, explanations, suggestions guys?