Ok this is what I've done so far.I have replaced the water pump,Lower radiator hose,two hoses that connects to the heater core,a little one that connects to the water pump,replaced radiator cap,flushed it four times,put new anti-freeze in,I even bypassed the heater core hoses.and it still over heats I was told that if I put the thermostat back in it will stop cause some cars require a thermostat to where it won't overheat. Anyone have any other suggestions? I'm getting tiered of sinking money into this problem.

Since you have done everything else imaginable, the only thing left is the radiator itself. Considering the age of the car, there is a good chance that the horizontal tubes on the lower part of the radiator may be plugged. A Radiator shop will remove the side tanks and shove a rod through the tubes to remove obstructions. Weighing what a shop might charge, you might be better off with a new radiator. I put in a call to Auto Zone and got a price of about $113 for standard and $200 for "max cool". Wishing you a speedy and successful conclusion to this ordeal.

Thanks.But that's the route I didn't want to go but I guess I have no choice.And once again thanks.

I've replaced the radiator with a brand new one and still the temp gauge is reading hot.I'm beginning to think it isn't in my engine I'm thinking it's mabe my cooling temp. sending unit.makeing my temp.gauge read hot.Is this possible?

I must commend you for your determination in seeking the solution to a problem. Yes, it is possible for a gauge to fail or for a sending unit to go bad. Did you have other symptoms of overheating other than the gauge reading? These would include boiling over or the crackeling sounds of a very hot engine cooling when shut off. You have done everything under the sun to cure the problem, much of it prompted by advice offered on this forum by myself and others. If, it turns out to be just a faulty gauge/sending unit, you have my most sincere apology for failing to mention that possibility. We all just try to help. Wishing you the best.

Thanks for your commendation and I have had no other problems with overheating other than the gauge reading no boiling over or being hot.Thats OK if you forgot about the sending unit I forgot about it until yesterday, So again thanks very much for your and all the others for the help.

Ok.I replaced my cooling temp gauge and the gauge still reads hot could it be the cooling sending unit switch.Now I checked at auto zone and it controls the flow of the radiator and gauge.But the guy their said that the temp gauge and the switch do the same thing.But the switch cost 45.00 and the unit costed 4.86.Should I buy the switch or is the guy trying to get more money from me.

The response from the Auto Zone guy confuses me. I don't know how a coolant temp sensor could control the flow to the radiator. A sesor/switch would probably control the on/off for an electric fan, that you don't have. I did a short search of Auto Zone and Checker for a 1984 Mustang 2.3L 1BL non turbo. At AZ I found two coolant temp sensors: Wells SU201 @$18.99, abd a Sontech MTO488 @$16.99. At Checker I found sensors from $26.99 to $38.99. I would remove the old sensor, take it to AZ, and have them find the closest match. This ordeal is probably your punishment for sins committed in a past life. Good luck.

Don't you think that would be a long trip for me to make just to mach up a part lol.I live in Tn.But I put a new cooling temp. unit in the intake but what is the other for and where does it go.

If you had a really fast car, you could make it to AZ in under a day. I just noticed that I screwed up again. I had pulled up an 84 mustang instead of an 86. I went back to the Auto Zone site with correct year and part was the same. I went to their component locator, and they showed driver side, below valve cover, mounted in block. I imagine that your car would only take one sensor, mounted on the intake, or the block. Doesn't this make you just want to go out and buy a horse?

LOL Yes it does make me want to buy a horse.