Hi guys, I didn't get a chance to do the flow test last weekend as I had planned. But I will post a new message with what I find hopefully by this weekend.

I grabbed a new water pump from Napa just in case, since that's what my gut said even though it's not leaking as has been my previous experience with failing water pumps. It's promising to see other people have had the same issue and it's been with a non-pumping water pump, which makes total sense since I have a working thermostat yet no movement into the upper hose. And things were working fine in the system even without a hole drilled in the thermostat. Thanks for the inputs.