evaporator heat core

how do i know that my evaporator heat core is bad

 

Which one the evaporator core or heater core?

With a heater core leak you will typically have a strong antifreez coolant smell inside along with window fogging in colder temperatures and in some cases coolant leaking onto the floor.

An evaporator leak isn't as obvious, sometimes you will get a strong refrigerant oil smell when you first turn on the blower. If you have a refrigerant leak and it's not any external components (condenser, compressor, or lines) it may be the evaporator leaking.