I have a 2.16 Ghz Core 2 Duo white macbook i bought a few years ago. Recently its been having some pretty bad overheating issues with random shutdowns or the notice window popping up telling me to hold the power button down. I've been seing CPU temperatures of over 85 degrees Celsius and Heat-sink temps of 60+ on IstatPro! Im guessing the random shutdowns are due to overheating which could be a combination of dust and the old fan/heat-sink. Im taking it in to get repaired but I was wondering if i should buy the replacement parts myself instead of letting them install whatever they like. Are there better fans/heat-sinks than others for my macbook? Also is it necessary to replace the heat-sink and or the thermal paste as well? BTW im taking it to my university repair shop not the apple store for repairs. Cheers!