Ask Mac Questions and Get Answers from Experts ASAP
is it 4MDT or 4MOT? If it's 4MOT, it's probably the CPU fan has failed. How do you fix it? Well, you would have to crack open the iMac and replace that fan (or bring it into an Apple Store for repair). In order to provide more specific information I'd need to know what model or series iMac you have.
It could lead to components being subject to a higher thermal load than normal... whether that leads to eventual failure? Its possible... basically what will likely happen is the fan noise you are hearing is causing the fan to drop below a certain rotational speed. If it stops completely, the system will over heat and shut off. The intel CPUs in most iMacs (assuming you don't have one of the REALLY OLD Motorola CPU'ed iMacs) have a thermal diode which will shut the computer off if the CPU is overheating. Its designed to shut off before any damage occurs... however, once that happens, the system will basically be useless until that fan is rep
replaced because the system will keep overheating and turnig off on you.