What I understand from your question is that you are trying to determine whether it is your TSM HDD (traditional spinning media) or your fan that is making the noise.
The easiest way to do this is to remove the HDD and replace it with...well nothing.
Step 1: Remove the HDD.
This is pretty easy. Simply remove the screws on the bottom case of your MBP. There are 10. Make note of the top 3 going from right to left as they are much longer than the rest.
Once inside, you will easily the see the fans and the hard drive. Remove the bracket holding the hard drive in place and then disconnect the SATA cable connecting the drive to the logic board.
Step 2: Boot your machine
Reset your NVRAM (Comand+Option+P+R while turning on your computer). Your fans should spin up to max for a few moments.
You can also boot into Diagnostic mode (Hold the D while booting). It will test your fans and spin them up to max for a while.
Don't worry about not having a HDD installed, nothing is going to happen. In fact, you are going to boot it with the bottom facing up towards you. What's on the screen doesn't matter for this.
Step 3: Listen for the noise.
If you hear it, you can flip over the unclosed MBP and listen to the fan closely. If you hear noise, it is most likely it. Put your finger on the fan to stop the blade. If the noise goes away, there's your culprit.
If all is quiet, time to check the HDD
Step 4: Check the drive (if required)
Reinstall the hard drive and its retaining bracket but don't close the bottom. Reboot following just like you did in Step 2. You can boot it with the bottom off and the lid open. You are more concerned with the goings on inside rather than what is on the screen. You won't be able to stop the drive from spinning, but you will be able to hear it much more clearly with it open. If it is making noise, that is your culprit and you will want to change it right away.
I just this week upgraded my MBP (late 2009) to an SSD and not only is it quieter, and cooler, it is blazing fast. In my instance, the HDD made a really horrible noise then the MBP stopped working. Here's the drive I used; it installed in about 10 minutes max. I did a clean install of El Capitan then transferred my over only my data; I opted to reinstall my applications.