I have been smelling antifreeze through my vents since the end of last winter, very faint smell. So I think, ok, around fall ill replace my heater core. Well, tonight it took off the cover to the heater core expecting to see an antifreeze residue, but it is dry as can be and the heater core looks good. I start to smell antifreeze when I tire the temp from anything but all the way to cold. I assume this could be still a pinhole leak in the heater core, but the two heater lines are being a pita to get off because of some silo me type material all around it. So what do you guys think, leak, or no leak? No film is left on any window.

 

If you can see the back of the heater core where the hoses connect, sometimes they deteriorate and leave just a small film or residue around the fittings. All it needs is a tiny hole to blow steam from and you will get the smell and not necessarily a leak.

 

I had a hose leak right at the core. All the bad core symptoms but the water leaked outside.

 

I did end up finding where it was coming from, it was a tiny tiny leak in the bottom corner of the heater core, like you guys said, just enough to smell but not have a drip.

 

Got it in along with a new fan clutch, thanks for your help.