You are correct that this drain plug is on the right side of the engine block. It will be in the coolant passage as it is there to drain the coolant out of the block. However, this is not required in order to flush the system.
Basically this plug is there for when someone is just draining and filling the cooling system. It allows you to get the coolant out of the block. However, if you flush the system then that is not necessary. Here is a guide that helps with this:
If you can't flush it and just drain the radiator and then refill it with water only (no coolant) and then drain it a couple more times until the water comes out clear, then that will be the same effect. This drain plug is there to make this easier but as long as you get the old coolant out and new coolant in, the end result will be the same.
I attached the entire process below for your review.
Let us know if you have questions. Thanks
Images (Click to enlarge)
Sunday, December 13th, 2020 AT 7:20 AM