Heater core smells bad, but...

[WSOakes]

I am not seeing other signs of a leaking core. No coolant loss that I can detect, no steam or goo on the windshield, and no moisture on the bottom of the core. The bottom of the core is quite dark colored, however. But in spite of all of this, I do get a pretty strong odor of what is probably antifreeze when I activate heat mode. I can't say that the smell is definitely antifreeze, though: perhaps the previous owner dropped a urinal cake down the vent? But it is definitely a sweet-smelling odor.

My question is, is it possible to have a leaking core that would set off a pretty pronounced smell but have no visible symptoms?

I know the cores aren't all that tough to replace so maybe I should just bite the bullet as a preventative measure.

Thanks, folks!

[JRL]

If it walks like a duck, etc.
You need a new heater core.
It's probably just starting to leak at the joints but not enough to drop on the floor.....(yet!)
It will do so soon so replace it.

It's not a bad job, an hour or so if you're handy

[WSOakes]

Yeah, the whole duck thing did come to mind. Thanks--I'll get on it right away.