Next time you smell it go up to your reservoir bottle and see if its boiling off from the top of radiator cap vent tube down to your reservoir bottle then it it will boil out of the bottle vent tube and blow either the hot air or both fluid and air, if not the problem then look down on the driver side of the motor at the water pump and see if fluid is seeping down case towards oil filter, it could either be oil or antifreeze or both blowing by the pumps O ring seal, and if that's still not the case then look and see if you have a little steam out the exhaust