alright i supposedly have a blown headgasket on my 97 deville. i changed the oil today and it looked just fine not milky or anything. i followed the coolant directions in the manual, filled it up and then let it run with the cap off. i noticed big bubbles coming up and i heard that may be a sign of a blown headgasket. it started going into the overfill tube and leaking on the ground. any ideas would be greatly appreciated, i hope its just a thermostat.

You won't find coolant in the oil on a Northstar due to the design. Bubbles in the surge tank is not a good sign. Do a cylinder pressure check with compressed air in each cylinder to be sure.

thanks for the advice ranger, as far as the pressure check goes is that a do it yourself job or should i try and find a cadillac dealer, which is about 60 miles away.

Well it is a DIY job if you have a compressor. If you have a hose for a compression checking guage that has a quick disconnect on it, you can use that, or brake the porcaline off an old spark plug and gut it so all that is left is the shell. Grind the rolled edge off. Then use a 1/8 pipe tap and thread the inside. Put a 1/8 pipe thread nipple about 4" - 6" long in it and then a quick disconnect on the other end. With the plugs removed, drop a 12" long dowl rod into #1 cylinder and rotate the engine with a wrench on the crank damper bolt til the dowl comes to its highest point. That cylinder is now at TDC. Install the tool you just made into the spark plug hole and connect shop air to it. If it continues to flow air, then you are at TDC exhaust stroke and the air is escaping through the open exhaust valve. Rotate the crank another 360 deg and you will be at TDC compression. Now air it up again and leave it connected and the cylinder pressurized for about :15 min. Watch for bubbles in the surge tank. Do that on each cylinder. If any one seeps air into the cooling systen and eventually the surge tank, it is getting in there through a breach in the head gasket at that cylinder.

okayyyyyy, well that is not a diy job for me lol, thanks for explaining it to me though;).