my car keeps losing water but no puddle under my car any clue

its either in your floor board (heater core), leaking onto something hot and evaporating, or most likely a head gasket has failed and u are burning it off in the cylinders.

pop the radiator cap off, start the car, get to operating temp, you will see the coolant fall and or start to 'swirl' in the neck. if this does not happen check the upper hose..is it still hard? bad thermostat. no 'swirl' bad water pump, yes even new parts can be bad out of the box. finally find the lost coolant...check the coolant in the radiator, does it have oil in it? rainbow colors? do you have bubbles in the coolant? should see no bubbles...if so both warrant headgasket, do a compression test to verify. pull the dipstick for your oil, does it have any white milky stuff on or in the oil? Headgasket. does the car stumble and puff white smoke, headgasket.

it could be the water pump, my buddy's truck was leaking water and we checked the thermostat, heater core and we found out that when the water pump starts to fail, water will leak out of it. causing the vehicle to run hotter and, as it is, leak water. check it out just to be safe