Acer Aspire 4315, making noise near fan

You would need to open it, has the laptop been dropped? This is the only way I know that could cause this problem. I suggest you fix this problem because it will cause overheating of you chips, that will eventually cause failure. Opening a laptop is not for novice, unless you trust yourself you can do it, have it done in a shop that fixes laptops. Some electronic shop can do this for you at a resonable price.