Subaru - Legacy :: 2004 - Smell Of Antifreeze In Cabin When Air Temperature Is Below 15-20 Degrees

I have a 2004 Subaru Legacy Wagon with around 90,000 miles on it. I purchased the car in 2008 with about 26,000 miles on it. Starting two years ago, whenever the air temperature is below 15-20 degrees, my car will develop a smell of antifreeze in the cabin when I start it and let it warm up for a minute or two. It did not do it for the first winters I owned it. I have not been able to detect the smell outside of the vehicle, and I have not been able to detect the smell in the summer months, even if the car is left idling for several minutes. The White Whale (my cars name according to my wife) was worked on by my local mechanic (where the car was purchased) last winter. They considered and replaced the thermostat, a leaking (or at least they thought it was possibly leaking) hose, and then finally after consulting over the phone with the Subaru dealer that is a little over 45 miles from my house, decided that the problem was likely the head gasket.

So at around 65,000 miles I had the head gasket replaced by the Subaru dealer. Problem is, they replaced it in March, and the temps were high enough that I couldn't really tell if the fix had fixed the original problem or not. It had seemed that the smell was at least less intense, but hard to tell. So, here we are in the midst of January, yesterday the car started beautifully (which is one reason that I love this car) after sitting outside all night at -11 degrees Fahrenheit with wind chills down to below -30. Last winter, in these conditions, the smell would be so strong that I would get nauseated driving the entire 15 minutes to work.

This winter, since the repair, the smell seems limited to only the first idling time. After that, the cabin seems to get cleared out with fresh air, and the smell dissipates. There have never been any check engine lights, the oil and coolant levels have never been a problem, the temperature is never higher than just above the mid-line on the gauge which has stayed the same all throughout the time I've owned it, and performance has been completely unaffected by the smell, other than my performance as a driver when trying to navigate in a car that reeks of antifreeze. Also, I have never noticed what some describe as a haze or liquid building up on the windshield when a heater core goes out and my mechanics, both dealership and local, assured me that this was not the problem.