Loosing coolant slowly not from overflow or raidiator where from

How hot does it get in degrees F? Does the cooling fan work? If overheating, the cooling fan should be running. Any applicable trouble codes?
I saw what you replaced, I'd still want to check coolant flow through the system.
Could have air in the cooling system? Does the coolant boil or overflow? You could have combustion gases in the coolant caused by a faulty gasket?

Coolant has to be put into the coolant reservoir.

then you need to replace it

Physically look in the radiator under the cap(if one exsist's) when cool, for coolant level, and check the valve in the cap for sticking. If air is present in the radiator it can't get out, and more coolant can't get in,(from the overflow). Either clean the cap or replace it and check that it is the CORRECT cap.

If radiator is low on coolant fill it to overflowing, replace cap, and check that coolant overflow is filled to the COLD line or mark. The overflow is normally where you would add coolant. (never overfill the overflow)After refilling as outlined above, check the level every morning for 2 or 3 days until coolant level stops dropping below the cold mark and add coolant to the overflow ONLY. Do not open the radiator cap. Also, if you have even a tiny coolant leak anywhere in the system, air will get drawn in, instead of coolant from the overflow.

For more OVERHEATING PROBLEMS try these...
Radiator fins dirty, clean with a strong stream of water, not high pressure water.
Radiator clogged, try backflushing it, or replace.
Thermostat stuck open or shut, replace it.
Water pump worn out, can no longer move enough coolant, replace it.
Fan shroud broken or missing....
Electric Fan(s) not working, Check the fan, relay, fuse and engine temperature sensor's.
Belt driven fan, belt slipping, fan clutch is bad, fan blades have flattened out.
Air dam under front bumper is gone, loose, or broken. It actually has a purpose other than scraping on the driveway or curbs. It forces air up into and thru the condenser and radiator. If it's loose, airflow can actually push it out of place making it useless or blocking the airflow. Along with that, there may also be a plastic piece attached to the bottom of, and wraps up behind the bumper. If it

Sounds like there is air trapped in the system. On a COLD engine, remove the radiator cap, and check the level. If it's low, slowly add coolant until the rad is filled right to the top, then cap it. Top up coolant overflow bottle if required. Start the engine. As the engine reaches operating temperature, the coolant level in the overflow bottle should rise. If it doesn't, it means that all the air is not yet 'burped' out of the system. Provided that the radiator cap is good, and that the coolant level is maintained at the proper level, the system should eventually expel all the air. Hope this helps. Good luck.

YOU NEED BLEED AIR OUT THE COOLING SYSTEM.WAIT TO ENGINE COOL DOWN.YOUR VECHICLE YOU HAVE TO POUR COOLANT IN THE COOLANT OVERFLOW JUG UNTIL COOLANT LEVEL STAY AT THE FULL COLD MARK.THEN START ENGINE LET IT IDLE A FEW MINUTES WATCH COOLANT IN THE OVERFLOW JUG WHEN IT DROPS ADD MORE COOLANT UNTIL COOLANT LEVEL STAY AT FULL COLD MARK.WHEN COOLANT LEVEL STOP DROPPING IN OVERFLOW JUG.SCREW RADIATOR CAP BACK ON OVERFLOW JUG WATCH ENGINE COOLANT TEMPERATURE GAUGE AS COOLANT TEMPERATURE START CLIMBING TURN OFF ENGINE LET IT SET A WHILE KEEP FROM GETTING SCALDED.TAKE LARGE RAG PLACE OVER COOLANT OVERFLOW JUG CAP SLOWLY OPEN RADIATOR CAP A LITTLE AT A TIME UNTIL PRESSURE RELEASE.REMOVE OVER FLOW JUG CAP.ADD MORE COOLANT UNTIL COOLANT LEVEL AT THE FUL COLD MARK ON THE OVERFLOW JUG.THEN SCREW CAP BACK ON THE OVERFLOW JUG.START ENGINE LET IT IDLE AGAIN WATCH ENGINE COOLANT TEMPERATURE GAUGE WHEN TEMPERATURE GAUGE START CLIMBING.TURN OFF ENGINE WAIT A WHILE.CHECK COOLANT LEVEL IN THE OVER FLOW JUG.DO THIS PROCEDURE UNTIL THE COOLANT LEVEL IN THE COOLANT OVERFLOW JUG STOP DROPPING AND STAY AT FULL COLD MARK,WHEN THE TOP RADIATOR HOSE GET HOT THERMOSTAT OPENING AIR IS OUT THE COOLANT SYSTEM. WHEN ENGINE COOLS DOWN.CHECK COOLANT OVERFLOW JUG COOLANT MUST BE IN THE COOLANT OVER FLOW JUG AT THE FULL COLD MARK WHEN ENGINE COLD. DONT .DONT OVERFILL COOLANT OVERFLOW JUG.KEEP COOLANT IN THE OVERFLOW JUG IF YOU LET COOLANT OVERFLOW JUG RUN DRY AIR WILL BE DRAW IN COOLANT SYSTEM CAUSE ENGINE TO OVERHEAT.

put 1 cup of bleach and drive 1 day.open pittcock at bottom of radiater and drain.replace with proper coolant

From the radiator cap, there should be some sort of hose that goes to a coolant overflow jug. If not there has to be a container easily to get to that holds the coolant overflow.
If you fill the radiator full, it should work, unless jug is empty.

it's your heater core lines. the 2 lines that come out of the fire wall on the passenger side under the hood.

You will find that under the hood either right by the battery there is a fuse box or by the coolant overflow bottle. Good luck.