radiator overpressurized

[bigfry]

I am working on a 89' galant. It is building way to much pressure in the radiator/cooling system. It has a new(correct) water pump, I have tried several new thermostats and without thermostat. I have also tried several new radiator caps. The problem is not that it is overheating. Soon as you start the vehicle it starts pumping water out the overflow tube. There is too much pressure soon as you start it so engine heat has nothing to do with it. I am certain the radiator is flowing properly ( I flushed it three times to be sure). So there is no restrictions, with no thermo, I can put a hose in the fill and water comes out the thermostat housing very easily so there is no restrictions. So it after a few minutes it has pumped enough water out that it now doesn't have enough fluid to cool it, then it starts getting hot. It builds so much pressure that if I cap it off where the overflow tube is closed it bursts a hose. Two hoses so far. I'm thinking its the head or head gasket. However there is no water on the spark plugs or in the oil and it is running nice and smoothly. I think I am procrastinating on the inevitable of having to remove the head, but this is a last ditch effort if anyone knows of anything else it could be, please help.

I'd say head gasket too, although it's a very strange set of symptoms

[buffAStheMonkey]

air in the radiator?
when the air in your radiator gets hot it will expand more then the liquid will. there for pushing the liquid out into the resivor and then when theres to much there onto the ground. it sounds like you no what your doing and you have probably done it. but take off the cap, turn on the car, blast the heat (so the fans start) and sit there for a half an hour just getting the bubbles out... you will loose alot of anti freez... but its gotta happen...

[bigfry]

naw, air alright, but from the cylinders. The head was badly pitted. I took it, had it machined and used a shim and put back together. Ran fine for a month then I believe (I wasn't the one driving it nor have I cared to check) it threw a rod or something a lot more severe. Thats been months ago though. I has brand new tires though. yea. Oh well. I'm letting my old lady drive my 95 caravan and I bought a 04 4wd silverado. That car was ready to rest. who knows someday it might live again, but I doubt it.

[bumflikmrfu]

I'd say warped head due to a bad overheat. you will know if you leave the radiator cap off and start the car. the radiator fluid will shoot out. this shouldn't happen!