Hag wrote my other laptops colling fan says its not functioning right how do i fix this. + rep

You need to get the fan replaced before you cause permanent heat damage. Stop using it until you get it fixed properly.
You can try and clean the fan, but this will not fix it if the fan motor is bad. In my opinion use a can of compressed air to clean out your fan.

For possible temporary use an external fan will certainly provide some cooling but the problem is a heat build up inside the laptop. An external fan probably won't do much to vent the internal heat to the outside. Heat sensitive units like the CPU and GPU could fail.

Good luck with your problem, hope I could help!