What would cause the antifreeze not to go back into the radiator from the overflow bottle in a 1995 ford taurus and how can it be fixed ? it has a new radiator, new thermostat and new hoses

Replace radiator cap , it's weak an not letting system build to normal pressure . Air in system !

Radiator doesn't have a cap the system uses the cap on the overflow tank.

Stop me if this has NOTHING to do with your problem (or if it's already been solved)...I don't know a lot about cars so...My Ford Taurus kept overflowing antifreeze from the reservoir cap. Car started to over heat and kept spilling"/dumping" antifreeze every time I turned the car off. The antifreeze reservoir had been replaced less than a year prior, and water pump, radiator, etc looked at. I got a free estimate that stated my water pump was NOT the issue, but I did need a new radiator and my reservoir tank needed to be replaced (again)....$800 parts and labor.... However...I noticed the overflow holes on the tank, and also that the orange liquid (antifreeze), was also spilled around the cap lid. I also noticed the CAP on the antifreeze reservoir would loosen when tightened completely- hence, not sealing correctly. So I went to the dealer, bought a new reservoir cap for $15, replaced it, and never had an issue after! I also found out that the CAP was a DEALER PART ONLY, and when the tank itself was replaced, the CAP was the OLD one! Problem fixed! Maybe it's similar? Or something "more serious".

The overflow drains and picks up coolant from the overflow bottle, or coolant resevoir. This is the same bottle where you top off your antifreeze. Usually located near the radiator.

You may have a leaking hose from the overflow bottle, or there maybe a crack in the overflow bottle itself. I've replaced a few of those because they had cracked.

When you top off the radiator you fill it to the neck where the cap goes. When the engine heats up the antifreeze eventually will distribute and the excess will go into the overflow bottle.

After the car cools, it will draw the antifreeze from the overflow tank into the radiator. Then check the level line on the overflow bottle(tank) for the normal amount of antifreeze per marks on the bottle.

You should have your radiator cap checked for its pressure rating. Use the type of cap which allows for an overflow system. The older caps would not let the antifreeze flow both ways.

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Removal

CAUTION: Do not mix Standard (green) Coolant with Extended Life Coolant (orange). If mixing occurs, drain engine cooling system and refill with originally equipped coolant type. If this contamination occurs, the service change interval on Extended Life Coolant will be reduced from 6 years/150,000 miles to 3 years/30,000 miles.

1. Drain radiator until engine coolant is out of degas bottle. Disconnect radiator overflow hose and engine coolant vent hose at degas bottle.
2. Remove power steering oil reservoir retaining screws and position power steering oil reservoir out of the way.
3. Remove degas bottle return hose and clamp. Remove degas bottle retainers and remove degas bottle.

Installation

1. Position degas bottle in vehicle and install retaining screw and nut. Tighten retaining bolt and nut to 9-12 Nm (80-106 inch lbs.)
2. Connect degas bottle hose and clamp to degas bottle.
3. Position power steering oil reservoir onto degas bottle and install retaining screws securely.
4. Connect radiator overflow hose and engine coolant vent hose to degas bottle.

My friend had a 1999 taurus and had the same problem, his coolant would leak from around the overflow bottle because the system was backing up. His problem was a partially plugged radiator. I know this probably isnt the news you wanted to hear, but I'm pretty sure thats going to be your problem. sounds like you've replaced everthing else short of the radiator and water pump. Good thing is i remember him saying it was reasonalbly priced, so good luck.

Heater not working sounds like a blower motor or heating core. Make sure that your antifreeze is green and mix 50/50 with water, now check and sqeeze your hoses running from and to the Radiator and if its VERY hard and has a crunch sound, it's blocked up, use radiator flush and follow directions, If not than look into the Thermostat b/c if it needs repaired than it will stick and let enough fluid into the engine so that it does not overheat yet with the pressure will back up into the resevoir. My new thermostat is a 140 degree and i've never soon my temp meter get to half way after that.