Macbook Pro 13' makes a grinding noise?

[hellothere231]

Recently, I've been noticing that my Macbook Pro 13' Late 2011 model is making a grinding noise. It usually happens when the fans are on. If the noise is coming from the fans (which i think it is,) what is it grinding? Can someone help? 😕

 

[Ih8reno]

Try opening it and see if something is caught in the fan