Q: Why is the fan on my MacBook Pro is running constantly and very loud?

Open Activity Monitor in the Utilities folder.  Select All Processes from the Processes dropdown menu.  Click twice on the CPU% column header to display in descending order.  If you find a process using a large amount of CPU time (>=70,) then select the process and click on the Quit icon in the toolbar.  Click on the Force Quit button to kill the process.  See if that helps.  Be sure to note the name of the runaway process so you can track down the cause of the problem.

Intel-based Macs: Resetting the System Management Controller (SMC)

ive done that numerous times on this process thats running at 355 cpu. it does not quit. keeps popping back up right after. any advice?

This thread is 3 years old. I suggest you start  a "New" thread.

In your new thread post some details, such as the name of the excess CPU using process.

Also please post the output of EtreCheck

<http://etrecheck.com>