Radiator fan not turning on when hot

That would probably mean the radiator is clogged up and that sensor is never seeing the hottest coolant.

Wrenchtech thank you so much. So i literally just thought about that and decided to pull down the radiator again, this time, i cleaned the radiator with water and run water through it through it hopping it will clear anything that clogged it up. Will retry radiator tomorrow... Do you think that is sufficient?.....

also how does the fluid usually run through the radiator, is it from thermostat, to radiator then cool by fan then to the thermo fan switch then out the radiator, or is it the other way around.

lastly after i fit up back the radiator how do i bleed out the air? the vehicle doesnt come with a bleeder. What i did previously was let the vehicle warm up with radiator cap off and anytime, topping up if the coolant level drops. Is that also sufficient?

If the radiator really is blocked up, that likely will not help. It will be crusted up pretty solid.
We do not have that vehicle here in the US so I cannot give you any details about the system.

so the fact that the water is now flowing through it properly does not prove that it is unblocked?

Update fan is now working thanks for your help. Last night i soaked it in some vinegar, and this morning i wash it out again. I fitted up back everything, and it seem like air was in the system so i tried to bleed it out by removing the radiator cap. It still did not turn on, so after a while, i decided to rev the car up with radiator cap off and i realize the coolant level went down so i assume there was air still left in engine block. So i rev and top up, rev and top up until i could not top up any more. Then i covered the radiator cap but left the reservoir cap off. Then i took a short drive down the road at high rpm's, maxing my first and second gear. By the end of the road i heard the fan came in. Open the bonnet there and then and in fact the fan was running. I high rev up the road back. I reach back, and carefully remove the radiator cap (keep in mind the radiator cap was not that hot, because i only put it on to go down the road and back, less than two minutes total). I remove the radiator cap in hopes that if more air is in the system i would let it release. Rev up the car while it is in neutral, the level was basically constant. So i shut off the engine, re-cover the radiator, re-cover the reservoir as well, gave it five minutes rest time. Then start the engine one last time, not revving, just a normal start and waited to see if the fan would chip in which it did. So far so good. Thanks again Wrenchtech for all the help.

You are welcome.