Fan Issue and stuttering even after SMC and PRAM Reset

Hi,

I have a Medio 2013 Macbook Air i5, 4gb ram, 128 SSD.

Recently the fans started spinning up to 6500 rpm (I use Monity to check), that is full speed. usually it starts right as i turn on the laptop - around half way through the loading bar the fan starts spinning up, by the time i hit the log in screen its at full throttle (Mind you that takes around 7-12 seconds from cold boot).

The computer is also very slow once this happens, and even simple tasks like opening a tab in google chrome makes it stutter, lag, and shw the spinning rainbow wheel of death (srwd from now on).

I have not yet reformatted the laptop, because i get an error that it failed everytime i try. another issue i suppose? But i am going to reinstall OSX and see if that does anything.

I heard that this is a common issue and that an SMC reset should fix it - sometimes it does, but only for a few hours and it starts back up and the computer slows back down. When this happens Monity shows CPU System usage as 70+ %, as if OSX is using the entire cpu for something.

I did a PRAM reset as well with no changes.

Additional info:

Do i need a new battery? I'm uncertain of where the SMC is located on an Air.

My charger uses a little converter bit, which im not sure is standard on macbook air chargers, but it is made by apple so it shouldnt be a problem.

I'm new to mac, so i am not sure why or what i can do. Any help is greatly apprecieated !

MacBook Air, OS X El Capitan (10.11.3), Medio 2013