It usually works fine, provided you have a motherboard with manual timing and voltage adjustments and are willing to accept looser timings or higher voltage than the label says.
If it turns out that's what's required to get them to work together, then you could decide afterwards if it's worth it to you to remove the 8GB sticks.
Try them all together see if the pc will boot if it does see what speed has been selected.I have an ADATA D60g 8gb x 2 RAM with 16-18-18-36 timings 3200mhz and was looking to upgrade. Will adding a 16gb x 2 3200mhz CL 16-20-20 be alright? Or should I just put in the 16gb x 2 and remove the 8gb x 2?
No, that only gives you the overclocking profile speeds. Manual settings are required if you want to be sure they will work together. If you don't have those, you could always just try it and if it doesn't work just remove the 8GB sticks.
name and model of both ram kit theyy should have same jedec and voltages to work or system will not run as it should .