headgasket coolant leak

My antifreeze/coolant is leaking into the engine and causing my car to overheat. I just began taking my engine apart and I was wonder which particular headgasket is respondable for coolant/antifreeze leaks.....

So far I took off the very top of the engine, the metal plate that say 3100 on the top of it.........And I notice that on one side of it the plastic gasket seperated.......And the bolts were very lose

The 3100 is known to leak at the intake gaskets, where the intake meets the head. If you severely overheated the engine you could have blown a head gasket. You will have to pull the lower intake. The damage will be to the coolant passage parts of the seal, at the end of the gasket where the thermostat is (most of the time). You'll also have to remove the pushrods and rocker arms to change the gaskets. Be VERY carefully because the pushrods are different lengths for the intake and exhaust valves. If you put them back wrong, you will bend valves and pushrods. Also, the bolts that hold the rockerarms are supposed to be replaced if you loosen them. They do make a special tool to remove the pushrods, that might be available as a loan-a-tool at a chain parts store. To check for a blown head gasket, I remove the pushrods (and rocker arms, if necessary) and do a cylinder leakdown test. But you have to have an air compressor and a leakdown tester to do this. Before you remove the rockers and pushrods, do a compression test. This might tell you, especially if it is low on the center cylinders. If their is any doubt I would remove the heads, have the surface machined (or rebuild the heads) and replace the head gaskets.