MY fans are noisy after cleaning them

[stirep]

So my fans were very dirty and dusty so i took the time to clean them, but now all they do are getting noisy whenever i do something on my computer it could even be loading a youtube video or opening a program.

What is the problem?

 

[Nine Layer Nige]

Is the noise due to the fan tips hitting the housing or is the noise due to airflow turbulence ?
Please describe "noise"

 

[stirep]

Is the noise due to the fan tips hitting the housing or is the noise due to airflow turbulence ?
Please describe "noise"

its due to the airflow i dont know i think my thermal paste is old but i ordered a new one and its on the way but i still wanted to ask to be sure, there is nothing hitting anything the fans are very good and works very good but its just the noise of the fans working so hard everytime i do something