Generally you can smell coolant burning or coming out of the tailpipe if your head gasket is leaking, you will get some moisture out of the tail pipe at first and for alittle while afterwards, this is just condensation and the catalytic convertor working like it should, if after running about 30 minutes or so in cold weather you are still puffing out a good amount of steam and it smells funny, that you might want to have it looked at. You can also check the spark plugs, if you have one or two plugs really clean, with no carbon or black colored look to them, then get it checket out. When water enters the combustion chamber, it will clean off any carbon deposits. Thats not good if it's in one or two cylinders. Not good either if it's in all of them and you didn't do it,,, Did this help out any? Did you get enough information to check for a blown headgasket? /forums/images/graemlins/waytogo.gif