blown head/gasket/ :(

[jason]

Hi,
i was investigating a small miss in the engine that was seeming to become more frequent over the last 2 weeks. running the motor without the radiator cap on it was able to watch the fluid appear ok until the thermostat opened. what started as a couple of bubbles turned into more frequent ones until it started overflowing to the point that the top of the radiator core became exposed. i had planned on going on a 400km road trip with my daughter to Maryborough on wed so that is out of the picture.
before i take the head off, is there a way to tell if the issue is a blown head gasket as opposed to a cracked head? at no point has the temp gauge gone higher than normal?

not having a good run with the boy so any news would be useful.
i had the head rebuilt under 2 years ago and have only done about 8k since so i am surprised that it could be the head - although i did drive it home (about 1km) in second a few weeks ago when the clutch cable went. kept it under 40 though.

[Psi_Wagon]

before you go to crazy, fill it up with water and run it again. mine did that exact same thing twice, due to a sticky thermostat.

other than that, take the plugs out and see what colour they are, red = bad (coolant in the combustion chamber). also a compression test

[jason]

will do. i did notice when i pulled the thermostat apart that the gasket was in pretty poor condition as though the coolant had seeped through it. what are your thoughts on running it without the thermostat?

j