your heater core is definitley leaking and your blower is pushing the vapor into the cabin. It will only get worse. You can minimize the smell by not running your heater or defroster, but you wont prevent the coolant from leaking and potentially getting worse. Sorry to say, the core will need pulled and repaired or replaced. Sometimes stop leak additives will solve the problem if its not too severe. I have never been a fan of them, its only a band aid in my view.
I'd appreciate a little advice. My Jeep Cherokee Sport's a/c stopped working last summer. We added freon (or whatever that coolant is called), it worked only slightly for a couple of days, then stopped again. We tried it again, and the same thing happened. Since I couldn't afford repairs, I just gave up and put the windows down.
Now that the weather is cold, I've discovered a problem with the heater. It works fabulously. I have no lack of heat at all. But it smells awful---just like anti-freeze. And I've noticed that sometimes the defroster leaves a film on the lower part of the windshield inside. If I could stand the smell, I wouldn't worry too much about it. But I know breathing this in can't be healthy, and I wonder what's going on in the mechanical parts of the car. What's tearing up that will, no doubt, only get worse? I've had to drive the car in icy conditions while wiping the frost off the inside of the windshield or roll the windows partly down to dilute the air from the heater. It's awful!
I've read something about a heater core, and it sounds expensive. I may not be able to afford to get it repaired. The parts, I might be able to handle, but a huge labor bill is out of the question at the moment. Can a vehicle still function if the heater core goes completely out?
Any advice would be helpful.
Thanks!

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