Car overheats loosing water changed radiator and hoses water pump fine and changed thermostat is it heater core or ac drain ?

Remove radiator cap when car is completely cold. Refill radiator look to see circulation when cap starts turn heater high. When thermostat opens water will be drawn from overflow into radiator. If this does not occur faulty thermostat is probable cause if no circulation change water pump. Refill water to correct levels and car should run correctly

Trying to understand from what you wrote..It sounds like something is not recirculating correctly.I would change out the thermostat first because it's the cheapest thing you can do..It might be getting stuck...not opening normal..When you said you turned on the heater and no hot air.. there's a hose right there at the thermostat that runs to your heater core usually under your glove box..If your not getting hot air then the water is not recirculating through your heater core..it could be a valve that is stuck when selecting heat that's not working also.. Flush your radiator..Open the radiator cap only after car motor has cooled down..Drain the radiator...There's a small turn valve nut at the bottom of it..Watch what comes out..is the water rusty color especially as it slows down from draining...They make radiator flush.. Also you can buy a thermostat that opens sooner...Like if yours is 180...you can buy one that opens at 160..A lot of cars are missing the black spoilers under the car that help push air up to keep motor cool..Make sure your water pump is good..Cat converter is not clogged in front of muffler...It will make you car run hot if it's getting clogged...Also Find out where your losing coolant...I've seen on holes in the heater core that leek from where your AC condensed water drips out..It will fool you and loose about a cup of water.. Smell the water your loosing also....if it's dripping from where the AC water is and you smell coolant...You have a bad heating core

I WOULD SAY NO BECAUSE WATER ONLY CIRCULATES WHEN YOU TURN ON THE HEATER, BUT IF YOUR VEHICHLE CONTINUES TO OVERHEAT IT COULD BE 5 THINGS. CLOGGED RADIATOR,RADIATER HOSES.THERMOSTAT,RADIATER FAN SENSOR OR THE WATER PUMP

drain coolant system locate heater cores hoses going through firewall you need to buy the radiator flush kit at any auto parts stores. remove heater cores hoses from one end or buy extra long heater hoses same size as heater core hoses in vechicle at auto parts store use the flush kit when you flush through one of the heater core hoses let the other hose drain in a drain pan when you use home garden hose use low water pressure dont use garden hose to the max or you will rupture heater core. your best bet let radiator shop flush whole coolant system. because heater cores hoses are in a tight spot.make sure engine off if you just going to flush out heater core only .after flushing heater core good time to replace heater core hoses.if job too hard or complicated let radiator shop flush out radiator the engine block and heater core because if radiator stopped up or engine block stopped up the gunk and rust will reenter plug up heater core.if you tight on money you can flush out your own radiator.drain out radiator using large drain pan. remove top radiator hose and remove bottom radiator hoses connect to water pump.use garden hose with flush kit part with water pressure not too high put garden hose to top radiator hose run water until clear water run out bottom radiator hose in drain pan,the flush out engine block remove thermostat.if you had another spare thermostat housing with RTV SILICONE SEALANT THAT HAS SET UP INSTALL THERMOSTAT HOUSING BACK TO ENGINE WITHOUT THERMOSTAT FLUSH OUT THE ENGINE BLOCK, WHEN DONE INSTALL NEW THERMOSTAT THEN INSTALL ORIGINAL THERMOSTAT HOUSING WITH NEW ORING WHICH YOU BUY AT DEALERSHIP.IF ALL SOUND COMPLICATED LET RADIATOR SHOP FLUSH OUT COOLANT SYSTEM.

It may be the drain for the ac check and see if it has antifreeze in whats leaking if not it is ac drain it supposed to drain when using the ac

does the heater work good, like real HOT when the truck is HOT? if not, flush the heater core with a water hose, both directions. Now when the truck is HOT open the hood and feel the air coming thorough the radiator, it should be HOT. if its not, the radiator may be plugged. If the mechanic has a Temp Gun, have him check the radiator temp, it should be uniformly HOT if you find cold spots (like if the radiator is 200f and there are places that are 150f) the radiator is plugged and "flushing" will do nothing.

the cooling systems consists of a radiator, radiator cap, water pump, thermostat, hoses, heater core and sometime a heater control valve that open water lines to heater core. You may need a cooling system flush if water pump, radiator have been replaced. flush the system.change the thermostat and have the heater core checked too if you can get to it.
does the cooling fan kick on to cool the radiator..check that too.replace radiator cap and check cooling fan yourself...let me know if need anything else.
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over heating can be caused by a number of things. your water pump could have died or the gaskets could have went on the water pump spilling your antifreeze every where. in which case you need to replace the water pump and gaskets. when you change the water pump you should replace the thermostat because they usually fail at the same time. your thermostat could have locked closed. in which case replace the thermostat. i recommend getting a fail safe thermostat so when it fails it gets locked open and then the car dose not overheat. your belt could have broke so your water pump wont turn. replace the belt. your radiator or hoses could be clogged with rust and sediments in which case you need to flush your radiator and change the anti freeze. you may be just low on anti freeze... so fill it up and see if it leaks anywhere. your tubes could have came off, be loose, or cracked and leaking; so replace or tighten them. your radiator could have a hole in it or leaking some where.. replace radiator. if you drive on dirt roads a lot the radiator could be full of sand and dirt could be full of mud if taken off road. just rinse the radiator out with soap and water. are your floor mats full of water or antifreeze? you could have a bad heater core. replace heater core. or you can cheat and take the two tubes off the heater core and splice them together. (which will leave you with no heat). your fan may have gone out so it wont cool the radiator. the last thing i can think of is very low or no oil in the motor. top off the oil.

heater core maybe blocked just take the hoses of heater core join them togeter and see if it works

Why was radiator replaced?Did it have heat before ? If it was plugged, the heater core may also be plugged. Try flushing it with a water hose in both directions. I dont know why the botton radiator hose would be cold, the radiator should be a uniform temp and the air coming through the radiator should be HOT, when the engine is at operating temp. What condition was the old coolant? if it was rusty, the water pump may have lower flow than normal.