Will opening my laptop to fix the fan void the warranty?

I have a Lenovo Ideapad 500-15ACZ. It's a 1 year limited warranty.

If it is within warranty period yes, opening it will void any warranty. Only exception is to open the slot where ram is located, to add more ram (or change it), or to change the HDD. However, opening the case totally voids any warranty…

Yes.

Why would you screw with something that can be fixed for free by a professional?