Find out where you're leaking. Anything that causes the coolant to leak out is cause for concern. Fill the radiator. Leave the radiator cap off and start the engine. Watch for bubbles. If there are quite a few bubbles and the coolant wants to blow out even before the engine gets warm, you might have a head gasket problem.
Blown head gasket? Air trapped in the system (hasn't bled out yet)? Wrong cap?
check the fan clutch
Where is it leaking? That pressure test sounds funny, why would you pressurize only the pump and radiator? If you are leaking coolant outside the engine, locate the source. If you are losing it from the radiator but cannot find a puddle suspect a head gasket problem. Check the Radiator cap first, if it is bad high pressure coolant will travel back to the overflow bottle.
Could be thermostat is not opening or collar on radiator is defective and needs to e resoldered sounds like a blown head gasket.
more than likely you need a new radiator for it, when you install it back flush the engine.
Is your fan coming on?
Inoperative radiator fans, bad water pump, failed headgasket?
It's very possible.
The top radiator hose is above the thermostat. If the top radiator hose is hot, the thermostat is opening. The thermostat is not the problem. Perhaps the radiator is clogged up or the water pump is bad. Look elsewhere.
Have flushed complete cooling system replaced water pump radiator thermostat clutch fan added 2gal straight anti freeze then filled to capacity with water and truck is still over heating. What else could possibly be wrong
If you have replaced the water pump then flush the radiator with CLR also check to see if the fan is working properly.
radiator fan, head gasket,
cooling system needs flushed out and a new thermostat installed, also if the radiator is still original it probably needs replaced or rodded out.
Could be a collapsed lower radiator hose, perhaps a bad thermostat.
you must be a wierdo.stupid.
did you check the radiator or the head gasket?
first of all, do you have the right thermostat? ie: winter, summer. if so i would get the radiator checked, it may be getting pluged.