Engine Problems....SOMEONE HELP!!!!

Alright, I have a 1999 Olds. Alero, 3.4 L engine that is heating up. There is no leaks that I have found, and I put dexcool in it already with a mixture of water like the manual says, 50/50....but for some reason it's depleting all my resevoir in just 2-3 days!!! I had a problem like this once, but it was the head gaskets then and the only way it stayed cool is when the air was on...but now, it overheats and depletes all the water in the resevoir... has anyone encountered a problem like this before or is there anyone that can help me? Im thinking its my thermostat, but Im not sure where thats located either...point is I NEED HELP!!!

Welcome to AF, if you are loosing coolant this could be the usual intake gasket issue or a head gasket, get it checked out asap. Almost all techs out there have seen this issue with the 3.1 and 3.4's of these years and should be familiar with the diagnostic process.