Is it possible for a heater core to leak enough to fog up the windows yet not make the inside of the car smell like antifreeze?

After reading smartin's post, I had a brainstorm...as some of you may remember, I've been complaining about the inside of the car getting really humid every time I put the ACC in "EC" mode, regardless of outside humidity and whether or not the a/c was on before or not. I did replace the drain tube (actually, with a funnel cut from an old oil container ) to no avail. I was wondering if the heater core could possibly be doing that...even though I don't recall ever smelling any antifreeze in the cab, and I don't think I've ever really lost any noticeable coolant...

Thoughts? Comments? Thanks in advance!

Also, if the heater core is bad, is it possible to repair it (no Bars Stop Leak ) as opposed to replacing it?

__________________
2001 VW Jetta TDI, 5 speed, daily driver
1991 Ford F-350, work in progress
1984 Ford F-250 4x4, 6.9l turbo diesel, 5 speed manual
Previous oilburners: 1980 IH Scout, 1984 E-350, 1985 M-B 300D, 1979 M-B 300SD, 1983 M-B 300D
Spark-free since 1999

The air conditioning does two things; it makes the interior cooler AND it removes moisture from the air. In EC mode you are NOT removing moisture.

If the fog were from a leaking heater core it would be slimy to the touch and would leave a film on the glass. It would be near impossible to have a heater core leaking that much and NOT smell anti-freeze unless you were not running anti-freeze in the cooling system.

Good luck,

Warden - All I know is that if there is a coolant leak of any kind any where - you will smell coolant - and you'll (of course) notice the loss of fluid. Since the "by-pass" it is dry inside - smell of coolant is lessening as I clean the residual.

Right, but what I'm getting is moisture being added to the air. If the car's been sitting for a few days and I get inside and fire her off and put the ACC unit from OFF to EC, the windows will fog up and peoples' skins will get sticky. I don't think it's because of me; my truck doesn't do anything like this and neither has anything else that I've owned.

It even does this in the desert, where there's no moisture in the outside air whatsoever.

I'm pretty sure that the a/c drains are happy; when I replaced the hose, I couldn't feel any blockage in the tube leading to the hose, and last I checked, I am getting some water coming out of the bottom of the car with the a/c on.

I think I'll next try running the ACC in EC mode for a prolonged time, with the car sitting in the driveway idling...I can't do this on the road because the windshield will fog up in a manner of seconds, but maybe the system just needs to be run for a while...?

Warden,
My car does this as well but not so bad that your skin feels clammy. I have checked the ac drain, looked for water leaks, etc. and there is no excess moisture that I can find anywhere. My solution has been to open the window/sunroof and let the fresh air in for 5-10minutes then when I close the windows and use the EC mode there are no issues. If I run with the ac compressor engaged (normal mode?) the humidity clears immediately. Incidentally I have a very small heater core leak as when I first run the heat I get a whiff of coolant that goes away in a few minutes. No film on the windows though so it must be very small. RT

__________________
When all else fails, vote from the rooftops!
84' Mercedes Benz 300D Anthracite/black, 171K
03' Volkswagen Jetta TDI blue/black, 93K
93' Chevrolet C2500HD ExCab 6.5TD, Two-tone blue, 252K

Warden,

The one and only time that I had a similar problem, I removed the dash and extracted the heater core. It was weeping slightly around the rubber seal where it is crimped like on the main radiator.

I took it down to a local radiator shop, where they recrimped the seals, pressure tested it and gave it back to me with no charge.

It's a chore to remove the dash but if your'e fed up with the moisture, there's no other practical way. Nix on the Barr's Leak.
While you're going through all this it might be the perfect time to replace the windshield rubber, if needed.

Ben

__________________
www.reproduce100s.com

on a W123 chassis, where do the A/C drains come out ? water is coming down the left side of my transmission only. I'm wondering if some water isn't backing up.

__________________
David McDonald
1981 240D
1985 300D (wrecked)
1985 300TD 365,000 miles
1969 Mustang Fastback

At least on mine, the a/c drains out directly above the center of the tranny. I would assume that, if the water's only dripping down the left side, the car's on a slight angle to the left.

I second the condensation theory, especially if the windshield isn't slimy. The drains don't drain everything, and all it takes is a bit of rain or dew (or snow around here - I get "the fog" in the winter in every vehicle parked outside). Rwthomas1's trick is what I do. Also make sure the system is set up to let fresh air in, not the recirculation "sauna" mode.

__________________
daBenz - 1970 220D