Overheating
 

I have a 1990 mk3 supra. Ive changed the hoses, thermostat,waterpump, and radiator cap. What happens is that once at running temperature the over flow tank gets full from the radiator but the radiator never pulls it back. So the tank just overflows spraying coolant everywhere and then the engine gets hot from lack of coolant. I think the head gasket might be the problem. HELP please if anyone has experienced this. Thnks, Ed.

vAPOR lOCK - sounds like your thermostat might be sticking. you could have a shop do a pressure check. DOes the coolant have any Brown'ness to it. OR look like poop soup this is a signal for a Blown Head Gasket (ps. you coolant would keep running throught the system picking up more oil and making it got hotter faster.
Did you check the Radiator cap and get the exact same psi rating ( i F-'d that up once before) it makes a substantial differance.
oil in coolent = BHG
Collant overflow = Stuck T-stat, bad rad cap.
It sounds more and more like a bad thermostat stopping the flow of coolant at the bottom of the system. .
Let us know what happens

13psi on the radiator cap, and just because that's what the package says doesn't mean it's right... ALWAYS test new thermostats and radiator caps... it's too critical of a system not to.

I'm doubtful of it being the thermostat myself.

Test the coolant for acidity too, if it's a blown HG (which doesn't necessarily mean the oil is getting contaminated) the coolant system may be getting pumped full of exhaust gasses.

Check the radiator for blockages.

i had an overheating prob on my 89. ended up being the head gasget. the gasget failed right near a coolant port and was shoving air into the coolant and formed an air bubble under the therm. and caused the coolant to boil off and overheat.

Id have to say its likely hg. Do the check for acidity mentioned and see, also does your heater work? Most airlocks tend to be around the heater core and back of the head. Gurgling/waterfall sound could be another clue.
Hope im way off and its simple but my moneys still firmly on hg...