Right fan rattling

Hello, My right fan is making a rattling sound on low speed and medium speed. Seems that a lot of people are having the same issue but I couldn't find any resolution in the other threads. I'm hearing the noise always when not doing anything and it gets a bit louder when I for example open Visual Studio or watch youtube. I want to know your opinion and if it's safe to open it so I don't lose warranty. Regards, Advan