Coolant Smell only when running heat

[LizzyTheLez]

I am having a similar problem with my ltz hatch.
when I have the heater on sometimes I can smell it, mainly when im driving to work and back (15 mins one way).
only say that because I just took a trip from texas to lousiana 4 hr drive both my wife and I did not smell burning 3 days later on my way home from work, I was just about to pull up to the house and could smell it.
recently have changed the radiator, upper radiator hose, water pump, thermostat and thermostat housing, inner and outer outlet pipes to throttle body finally got the car to not lose coolant and not run hot only for it to have a burning smell when running the heater.
have no oil haze on the windshield that i have noticed atleast.

could it still be the heater core or heater core seal?

 

[jimmykarlbird]

Did anyone ever determine a definitive fix for this? I've been reading online a ton the last couple weeks, as my car started smelling heavily of coolant, then the inside of the windows began fogging up. I had scheduled to bring it in last week, but then it started running fine. Had a buddy look at it, and he was stumped...no smell...no leaks he could find. Now that the weather has gotten much colder again, it's giving me the strong stench of burned coolant again. If this was truly the heater core leaking, why would it run fine for the last week or so and then come back.

 

[Nvmarv]

Heator core

Usually its the heater core especially if you get a film on windshield in morning.. Should start to see coolant in passenger compartment on floor..ie it will be moist