what the heck is going on? changed the thermostat and the thing started smoking, no coolant loss, no overheating, no oil milkshake. what else could it be. car has a 3.8 with auto w/overdrive. also if it is the head gaskets. can i replace them without rebuilding. guy told me that if i did it would blow my rings out.

you can change them with out rebuilding it. You will want to change the oil in it of course, and flush the coolant system to get out any contamination. Run it for awhile after you are done to burn off any coolant still sitting in the cylinders if any, do not race the engine, maintain idle to build up oil pressure. Before you do any of that, you want to find the leak if possible, it could be leaking in through the intake manifold gasket. Your best bet is to spend the 50 or 60 bucks to have a mechanic take a look at it, they can pressure test it for you and tell you which gasket it is and you can do the repair from there. If you don't want to do that, just replace all the gaskets in it at one time. The gaskets are cheap, the labor is what kills you on these repairs.