98 Lumina LTZ 3.8 water in oil

My car was running perfect, no engine noises, great performance, except I had that pesky 'what in the heck is happening with the coolant?" problem. The mileage is just under 100,000 so I thought I would buy a new rad cap along with the tune-up items. Right at 100,003,it started running rough on the freeway, my cervice engine soon light starts blinking and stays blinking until I pulled over at the next exit, The temperature gage right in the middle. (a friend of mine thought it or my thermostat was broken because it always pointed on cold) At the station it was running rough, and big white clouds of smoke was coming out of the exaust. I checked the coolant it was low, real low, but the engine didn't seem to be hot, I checked the oil after turning the car off, and it had gained about a quart of fluid. It was not milky, just a lot thinner. I started it back up, still running rough, and drove around the corner to my house. Before I turn this story into a novel, I'll tell you where I'm at now. I have got the upper and lower intake manifold off, I was convinced it had to be one of the gaskets. (Please don't ask about the compression check) I found no sign of blown gaskets, It looks like it had been worked on before. I found the water bypass pipe was broken, and someone just stuck it back it the hole and permatexed it. Well that's about it. Since I didn't do a compression check, what do I do now? Oh, and should I get some Halogen fluid along with those gaskets?
:banghead:

You've got a blown head gasket. If you didn't let it overheat, you can probably reuse the heads. 3800 head gaskets are fairly cheap. Another thing is to torque all the bolts properly or you'll be doing it again....

You could have a cracked upper plenum. Did you notice any coolant puddled up in the lower intake when you had the upper plenum off? When the plenum fails (around the EGR stovepipe tube) it will leak coolant into the drivers side rear cylinder, and make the car blow steam.

You could have a cracked upper plenum. Did you notice any coolant puddled up in the lower intake when you had the upper plenum off? When the plenum fails (around the EGR stovepipe tube) it will leak coolant into the drivers side rear cylinder, and make the car blow steam.

There was coolant puddled in the cylinders passenger/firewall side, no apparant evidence of steam or water leaks. My brother was going to help do a compression check but we could not get the compression fitting into the sparkplug hole. I called Chevy dealer asked if there was an adapter, they said no, called the parts place they said there is a fitting that has a longer thread body, had to order one. Sorry if the terminology is not correct, my first time working on my car. (I'm not too fond of mechanic'in yet)'