I'm not a mechanic / technician but the first thing I would check is the engine
oil ( see if the engine oil looks different than it does normally , milky looking
maybe , or if the oil level has gone up ) that would indicate the engine coolant
is leaking into the engine oil from perhaps a bad head gasket
Losing coolant in a vehicle is not a good thing. It is best to check all seals and all bends in tubing.
I think you would know if you needed a freeze out plug for you would be losing coolant & losing coolant would make your ride run hot.
have the head gasket replaced
Have it pressure tested and repair the leak.
If you are losing coolant, you probably have a bad cylinder head gasket. Too much coolant system pressure will drop your engine oil pressure.
either your radiator is leaking,head gaskit is leaking if it's your head gaskit leaking you will have water in your oil or water coming out your exhaust pipe,or you might have a freeze plug going bad.
First, where is it losing all the coolant ? Is it losing the coolant in the engine, or on the outside of the engine ? You must establish this first. What was the problem before ? Is the coolant leaking from the out side, like near the water pump, or from the large tube that goes into the water pump from the rad. hose ? Is there a problem with the thermostat ? When you replaced the pump, and put in the O- ring, did you put some silicone on the O-ring to help it seal ? Is it leaking from there. Check all the hoses and clamps and the rad. Good luck.
could have a crack in it that is leaking under pressure
If there really is no leak then it is likely a head gasket allowing coolant to leak into the cylinder and go out the exhaust as steam.
check your oil to see if you have coolant in it. if you do your intake gasket needs changed.
The internal and external conflict are Friends losing others and living through life with out problems
sounds like a leaking head gasket have a pressure chek done on cylinders and cooling system