over heating issue... possibly a head gasket?

so I have a over heating issue with my 92 3.0 and I haven't been able to figure out why.
Whats been done:
changed thermostat
checked for plugged radiatior
plugged coolant circulation

and none of that has changed it. itll overheat and blow coolant out the overflow after about 2 miles and say its overheated but the block will barely be warm to the touch. iv had people tell me that it might be a cracked head gasket that's allowing pressure to get into the cooling system and over pressurize and then over heat. I know the head gasket isn't "blown" because it has no symptoms in the oil or exhaust. any help would be MUCH appreciated. this is my first Toyota so im kinda learning as I go.

 

Does sound quite similar to a head gasket since it blows out coolant so fast. Most parts stores have a tool loan/rental system and they usually have what looks like a turkey baster which is used to check for and measure combustion gasses in the coolant. If the tester shows a positive indication, then the highest probability is a head gasket.

 

This is true, what about a water pump? And would the tool still get a reading if I JUST put in new collant?

 

Yes the test would pick up the presents of exhaust gasses in the new coolant. You could also pull the spark plugs, a very white deposit indicates coolant getting into the cylinder as does a sweet smell to the exhaust.

My guess is the coolant circulation is impeded, water pump impellers dissolved/eroded, collapsing or blocked lower radiator hose.