in my 01 i get a smell of antifreeze when dial in cab is set to hot and the t-stat is opening. doesnt happen when the temp is set to cold or when engine is cold with the dial on hot. even if the heat, defrost etc is off, if the temp control dial is on hot i smell it when the t-stat opens. im guessin its the heater core but doesnt antifreeze constantly flow through it? why would i only smell it sometimes? anyone else have similar problem?? p.s. not seeing any leaks anywhere. thanks.