Fog in my e30

[harv]

Ok, my 91 318is getts very foggy, so last winter I managed to get by with the ac on and a window cracked slightly. I figured it was the heatter core. Summer came and I put off the heatter core replacement. So this fall I replaced the heatter core and replaced the ac/recirc switch as the recirc switch would stick sometimes. Everything seems to work as it should except I'm still getting a lot of fog on the windows. I HAVE to use the ac to keep it clear. Wtf?

Any ideas?

John

[Ceeker]

If you keep the recirc on for any length of time the windows will begin to get foggy. with the recirc off the car is bringing fresh air into the cabin and taking stale air out. Recirc was kinda e30's way of a cabin filter that didn't come in the north amercan versions. I hear some without a/c had the cabin filter. So you'll just have to cycle it on and off time to time to clear it. this is a normal occurrence for many cars.
This is also affected with weather conditions. If there is lots of moisture in the air - cloudy, foggy, rainy - will increase the likelihood and frequency of fogging.

you can also use the defrost with heat to clear it. keep the recirc on for relatively short periods.

I get this in all my e30's when I run recirculation.

[harv]

Thanks for the reply. I guess I didn't specify the settings. This is happening with the heat on full hot, fan at 2 or 3, defrost full on, floor on or off depending on how cold my feet are, dash vents off, and recirculate off so it should be fresh air.

I do have a Luke box sub, could I have blocked a vent during the installation? I don't remember seeing anything back there.

John

[harv]

Bump?

[Chruby99]

Is there a smell of antifreeze in tha cab. Could be a pin hole leak in the heater core

[harv]

Already been there...

Thanks for the reply

I figured it was the heatter core. Summer came and I put off the heatter core replacement. So this fall I replaced the heatter core and replaced the ac/recirc switch as the recirc switch would stick sometimes.

John

[spdracrm3]

be sure the HVAC unit drain is working to drain condensate to outside ,if plugged the HVAC unit fills up with water from AC condensing moisture out of the air .then every time you run heater without AC it will fog badly. also if the drain is pinched or not routed to outside it could be draining onto your carpets where it is again picked up with heater on fogging up interior.
there is a short rubber hose on the bottom of the HVAC box that if connected properly and not plugged drains water to outside above the transmission .it not easy to get to from inside or outside unfortunately

[harv]

Thanks. From what I remember, when I did the heatter core I looked at that hose and it looked fine. But then again, I didn't see if it was plugged. No wet carpets so far.

John