JKSlow4

Hello All - I recently picked up an 05 Fx4. Love the truck in general minus the leaking 3rd brake light (hopefully got that one fixed.)

Now - on to my issue: Recently when I turn on the heater I get a sweet smell. I assumed it was antifreeze and that my heater core was going bad. However, I got the truck pressure tested and they said there are zero leaks with the cooling system - no issues whatsoever. None of the typical bad heater core symptoms (with the exception of the smell) are occurring. No fogging windows, no mist out of vents, the heater is running nice and strong - strong blowing heat works great.

According to the mechanic he said it is the Evaporator Core and that it is very dirty that is causing it to smell. I am very skeptical. Could this be the case? Why would it smell only with the heater and not the AC?

Any help or insight is appreciated.

Thanks!