Losing water, about a cup and a half per day. New cap. No apparent leaks . Renting pressure checking tester tomorrow.

 

welcome to the forum. do a compression check of all cylinders,( leaking head gasket), do a radiator pressure leak check (hose/radiator leak), check color of your oil not cream color, (is it making oil) are there any antifreeze smell in the cabin.(heater core).