Dell Inspiron 7577 Fan Problem

Throughout the previous few months or so I've seen that my PC's right-side (when seen from the back) fan has as often as possible been making a noisy humming clamor. The commotion will change in force and volume or occasionally vanish contingent upon how I slant my PC, and the clamor will generally disappear sooner or later.

Besides, I've seen that as of late my PC has had a lot higher inactive temperatures and will get exceptionally hot while gaming (85-90°C). Subsequent to warming up, my PC will keep on remaining hot for quite a while and doesn't chill off without a doubt (drifts around 70-80°C). While gaming, I will encounter times of outrageous unplayable slack, expanding in span and recurrence relying upon the interest of the game (which I expect to be my PC choking because of its powerlessness to sufficiently cool itself).

I have as of now cleaned the two fans and admissions, so this persuades me to think that one of the fans might have inadequacy of some kind or another. Be that as it may, the two fans seem, by all accounts, to be practical other than the humming. Does anybody have any idea about the thing that could be causing the high temperatures and slacking during games?

How might I approach taking care of this issue? Would it be a good idea for me to buy a cooling cushion and do a warm re-glue to assist my PC with cooling?

Let me know what should I do. Thanks in advance.