Q: My car over heats while idling but as soon as I turn AC lose of coolant, overheating, and my clutch becomes sticky and won't engae

Hi, recently my car has been over heating and an abundance of coolant is lost in my driveway. So right away I tried to find any tethered hoses or any signs of leaks. I even did a pressurized test to find any apparent leaks. Only to find a leak is coming from the top of my oil well. Where I cannot see any further. So I bought blue devil sealant to find it splattered all in my engine bay. So I decided to flush my whole cooling system, along with the heater core and changed out my thermostat. I run my AC and no issues there. But noticed that my temperature gauge shot up while idling. I figured it was my radiator changed that along with hoses. But still my car overheats but no leaks. Now I didn't change out the radiator fan assembly because I plugged it right to my battery and it works. I even changed out the fuses/relays but still my car over heats m? But when I don't use the AC my car runs fine, no over heating. But I've notice that it's harder to change gears or have em engage.

My car has 168000 miles.
My car has a manual transmission.