sometimes to coolant will turn rusty colored if exhaust gases are intering it, and it will stink like amonia VERY STRONG. like give you a nose bleed strong. but they wont always smell that way. that is just an indicator. like said above, check your coolant and see if its low. if it is low, top it off and check the level again (at the same engine temp as the first check. preferable cold so you dont get burned). exhaust naturally steams in the winter, but steam should be gone within 15 or so minutes of driving, if it steams constantly, no matter how long you've been driving, then there is a good chance you have a blown/leaking head gasket. take it to a shop, ask for a block test. they put a sniffer in the radiator and check for exhaust gases. also if its blown, after a long drive your radiator hose will be rock hard from all the pressure in the cooling system. hope this helps.