Too many problems to list...

[NoLeafClover]

I generally say (with any car) that it hasn't overheated until it's spewed coolant/Antifreeze/water. This zx does that as if it has bulimia.

[siteunseen]

That thing under the fuel rail that's leaking air could be the Fuel Pressure Regulator. https://www.google.com/search?q=280zx+fuel+pressure+regulator+location&tbm=isch&ei=deTMU87WLs6cyASPooDQCw They play a huge part in the fuel injection system. It should have a vacuum line coming off the intake manifold to it, if it doesn't and is leaking air you should fix that right off the bat. My '77's air filter housing is an early "Cold Air Intake" type, I think the ZXs are made a little different but that shouldn't be a problem, no leaks after the AFM is what is important, "un-metered air" will cause it to buck and cough. I would think your cooling problem isn't the radiator if it gets hot that quick, stuck thermostat, bad water pump or fan clutch. Spin the fan with your hands, if it free spins more than 2 rotations your fan clutch needs replacing. Take out the thermostat, crank it and watch the flow under the cap or lack of flow.

Sounds like cars I've had in the past. My Dad would say to "take the radiator cap off and drive another car under it, tighten the radiator cap and go". He could be a d i c k sometimes.

[NoLeafClover]

I'll post a pic when I get home around 7 or so pm of the hose. It leaks coolant when it decides to Spray any flu I'd otherwise it just hisses loudly. The clamps are new but I think the hose may be the wrong size. And as for the fan the one it has on it is electric and is wired to come on as soon as the key turns. The ther most at is brand new and it's a 180 as someone recommended to get. I'm thinking the gas tank may be dirty, because when I pulled the old fuel filter off after ml some clean fuel came out it became red and heavy with what appeared to be rust particulate.

[Zed Head]

I generally say (with any car) that it hasn't overheated until it's spewed coolant/Antifreeze/water. This zx does that as if it has bulimia.

It leaks coolant when it decides to Spray any flu I'd otherwise it just hisses loudly.

Blown head gasket is looking more likely. You're probably low on fluid and the "air" is actually exhaust gases leaking from the line from the thermostat housing that supplies the AAR heating block. The fluid then gets warm and expands until it can start spewing. There are no lines that would normally hiss air, then spew coolant. The cooling system will always be pressurized when the engine gets warm. The limit is typically 13 psi, set by the radiator cap.

Eurodat's suggestion in Post #25 is a good one. Take the cap off when cold, start the engine and watch. You might see bubbles and frothing. As the engine warms up though the coolant will expand and start to overflow.

"Next the heating problem. Remove the radiator cap and get the engine hot again. Check for bubbles escaping from the radiator. It a sign that the head gasket is leaking or cracks in the head. Its not 100% but its a good indication."