Trying to use Blue Devil head gasket repair, do I need to remove both thermostats?

Hello,

The front one is the thermostat and the back one is a water control valve.
Removing both would be ideal.
And anytime you have a gasket or a seal, you should replace it.

We did a helpful video on the Blue Devil head gasket sealer, it might give you some good insight.

https://youtu.be/Xi41RFMP8Ow

Please let me know of any questions.
Thank you.

So, should i put back on the thermostat housing and water control valve housing without the thermostat and water control valve and then add the blue devil and crank my car?

Yes, that should work.

Okay, i removed both thermostats & put both thermostat housings back on, put the Blue Devil Head Gasket Sealer in the radiator and topped it off with the proper 50/50 engine coolant/Antifreeze. Then i cranked the car, turned the heat all the way on and let it run for 35-45 minutes (until the temperature started going up and the coolant in the coolant reservoir was bubbling up out of the spout on the side of the tank) Should i install both of the new thermostats and gaskets then put the thermostat housings back and add more Head gasket Sealer and Coolant and crank it with the heat all the way on again? Or should i just install the new thermostats, put the housings back, fill the car with Coolant/Antifreeze and then crank it to see what happens?
Thanks

If it overheated again, then the sealant might not have worked. You can try adding some more sealer in case it was not sufficient.