after 45 minutes of driving,the fan should spin freely with the engine swtched off,that is if you have an electro-magnetic fan clutch .
on a viscous /fluid operated fan clutch ,you would expect a 1/4 turn after 45 minutes of driving.
freewheeling, if engine was cold
i get the feeling that your electromagnetic fan clutch is either faulty or been modified to stay on permanently in the hot weather conditions in singapore.
i know for a fact that in kenya,africa where we had equatorial hot climate,some people would throw out the thermostats and modify fan clutches to come on all the time-not a good idea as you lose engine performance/fuel economy and cause premature engine wear.