[Dngrsone]

I agree with Karl, it sounds like your lower intake manifold is cracked. Do not operate the vehicle any more, don't even crank it over. If a significant amount of coolant gets into a cylinder, you can incur serious damage.

If the vehicle was running when the big gush came, did it stop on its own? If so, you may already have a bent rod, blown piston or bent crankshaft.

A fairly quick way to see if there is would be to pull all the spark plugs and manually turn the crankshaft. I used a 1/2 inch drive ratchet with I think a 3/4 or 5/8 socket on an extension. You will have to turn the crankshaft at least two full revolutions to get each piston through the entire 4-stroke cycle. Taking the accessory belt off will make it easier to turn. Lift the vehicle and go through the wheel well.

If you can run the crank through the full cycle without an increase of resistance, then things are looking good. If the amount of resistance changes, then there is a lower-end problem and you'll need to have the engine pulled. If it looks good so far, you'll want to do compression checks on each cylinder and look for discrepancies-- if one or two cylinders show a lower pressure than the rest, or the pressure leaks out, then you have bigger problems.

If everything is going right and you want to replace the intake manifold yourself, there are a few threads in this forum that would be useful to read. You can search using key words (not necessarily all at once) intake manifold head gasket.