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Old 12-15-2016, 10:53 AM   #1
ChadTsunami
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Both windshields fog up excessively during winter months

Hi guys,

So I've been having this problem during the winter months since I bought the car. If I leave the car outside in under ~30 degree weather my windows fog up almost completely after awhile. Sometimes it gets so bad that I'll have ice form on the inside of the windshield.

Moisture is finding its way into the cabin somehow but not sure how I can determine this. I have tried using anti fog sprays which help a little and even tried the cat litter in a sock to soak the moisture but they provided only marginal improvements.


Do any of you guys have the same issue or suggestions to solve this?


Much appreciated!
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Old 12-15-2016, 12:02 PM   #2
jfoj
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4 most common moisture entry points in order based on my experience.

1. Door vapor barrier, most often the rear doors, but can happen to any door. If a window regulator has been replaced, almost guarantee this is a possible source. Check to see if there is water in the door jam after rain or car wash, jam should be dry, rear carpet can and my be wet. Remove floor mats and check carefully.

2. Sunroof drains possibly clogged. Search for testing and cleaning ideas.

3. Lower windsheild cowl plastic, often cracked at the base of the windshield, even if this is not the source of the current leak, it could be a problem in the future, best to inspect and correct now before it becomes a problem.

4. Cabin air filter box drains, either the cabin filter drains clogged or something wrong with the cabin filter or cabin filter installation. Not a very common problem, but can happen.
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Old 12-15-2016, 12:46 PM   #3
ChadTsunami
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Thanks for the suggestions jfoj!

1. I can't be certain that I have factory window regulators in this car but I think may be as I have not replaced them since I got it in March 2015. Either way the door jams have always been dry after rainy days so that looks good.

2. Sunroof drains. I think this actually may be part of the issue, I'll have to investigate and report back.

3. My lower windshield cowl is actually in rough shape so this may be contributing to the problem too. I'll def replace it.

4. I recently cleaned the cabin air filter drains so this should be good to go.


I'll work on checking the sunroof drains and replacing the windshield cowl and report back when I get some good results.


Thanks again for the help!
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Old 12-15-2016, 01:47 PM   #4
jdstrickland
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The windows fog up when you are not even in the car?

If you are in the car, then you need to turn the AC on while the heater is also on. The heater can easily overpower the AC, and the AC is a dehumidifier so this should prevent fog from building up inside. Turn the ventilation system on with the fan speed on HI. Set the temp to whatever you want, I think I would set mine to about 80 until I could not stand it anymore and then dial it back. Set the AC on, and set the air flow to the windshield. Turn the electric defroster on for the back window. This should clear the glass in pretty short order, then you can make adjustments to the settings that work better for supporting life as we know it.

The AC is a very important part of clearing the moisture from the inside of the car. I would assume that you also have the Recirculation set to on, this takes your hot breath and traps it inside of the car, making the humidity skyrocket. I understand why you would not want fresh air from outside because you are trying to heat very cold air; with the recirc turned on then the air goes around and around and the heater can do its job easier. I'm not sure this is actually true, but I am giving heater advice from the comfort of San Diego, so take it with a grain of salt. The point is, without regard to the possible leaks that the car might have, your hot breath is your worst enemy when it comes to foggy windows. You need to dehumidify the inside of the car, the AC is the tool for this. Set the temp to full hot with the AC on, the temp will be comfortable and the air will be dry, making the windows fog-free.

Fixing the leaks that the car might have will help cure the fog inside of a parked car, but a car that has hot bodies inside then there is nothing that is better than blasting the AC. When the windows clear, keep the AC on, but turn the fan down and change the vent selector.
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Old 12-15-2016, 04:05 PM   #5
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press the snowflake
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Old 12-16-2016, 03:55 AM   #6
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Make sure the HVAC is not on recirculating too.
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Old 12-16-2016, 04:28 AM   #7
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If carpets feel dry, check this spot:

Remove the rear floor mats
Remove the velcro discs that hold the mats in place
Stick a q-tip down in the holes to check for presence of water

This is where I found a lot of water in my car. I used a carpet shampooer with a hose attachment to suck out as much as I could. There was at least 1-2 quarts. In my case, the water was coming in through at least two locations: one or both of the rear vapor barriers, and through a bad seal in the roof antenna.

Also, there was one day that water got into the glove box and I have no idea how. It happened once about 6 years ago and never again.
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Old 12-16-2016, 05:51 AM   #8
jfoj
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Forget about all the talk about turning on the AC, even if the OP makes sure the AC is turned on, the car has a water leak problem. I have yet to find a BMW over 7 years old that does not have a water leak problem except for my wife E46 convertible so far!!

True having the AC/Snowflake on helps dry out the car, but of the inside of the windows are fogged up when you get in the car after sitting overnight, there is moisture in the car. If the windows fog up QUICKLY when you get into the car, there is moisture in the car.

Just put a humidity gauge in the car, it should match the outside humidity. Note, the colder it gets the lower the humidity get!!!

I think the 2 door/convertibles are far much less prone to water leaks.

The convertibles because they DO NOT have a sun roof and the coupe/convertible doors get used more.

I have do something with my X5 soon, but it is a bit late now in the season.

The rear drivers door vapor barrier is leaking, but I think I have another leak somewhere. I forgot about antenna as not all E46 have the BeeStinger or Shark Antenna.

It was 18F here yesterday and my rear drivers door gasket froze to the door jam and I could not open the door!!!

You guys in the arid location do not have the problems were have in other areas.
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Last edited by jfoj; 12-16-2016 at 05:58 AM.
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Old 12-16-2016, 04:54 PM   #9
IxNay
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This happens when I am driving my car in winter if I press the recirc button. If I leave recirc on for longer than a half hour my windows will begin to fog on cold days with the heat on, A/C off and recirc on.

If your recirc button is not working properly your windows will fog up on cold winter days when driving.
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Old 12-17-2016, 11:20 PM   #10
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press the snowflake
That would make a great bumper-sticker!

Or a tagline in a movie.
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Old 12-18-2016, 10:29 AM   #11
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Other things to consider - clean the inside of the glass. Condensation adheres to the the gunk the accumulates on the inside of the windshield. I typically just use water because some cleaners leave a residue that simply attracts condensate. Also, if it takes awhile before the fogging is apparent or significant, don't forget that by exhaling you and any passengers are adding water vapor to the cabin atmosphere and will condense just like any other water source.
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Old 12-18-2016, 10:43 AM   #12
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IF the front and rear glass as well as the sunroof glass are fogged up after the vehicle has sat overnight, then there is excessive moisture in the cabin due to a WATER LEAK!!

Real simple, real straight forward, no more discussion!!!!!
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Last edited by jfoj; 12-18-2016 at 10:44 AM.
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Old 12-18-2016, 03:08 PM   #13
IxNay
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Quote:
Originally Posted by jfoj View Post
IF the front and rear glass as well as the sunroof glass are fogged up after the vehicle has sat overnight, then there is excessive moisture in the cabin due to a WATER LEAK!!

Real simple, real straight forward, no more discussion!!!!!
If the reason the windows fog up is due to a water leak then there must be obvious signs of water intrusion such as wet carpets, floors or trunk and eventual bad odor as mold sets in. Have you checked all carpets and the trunk for signs of water?
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Old 12-18-2016, 03:17 PM   #14
jfoj
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Water intrusion is not always as obvious as one would think.

If the jute backing under the carpet gets wet, then often the carpet will be dry to the feel.

Also need to check in the trunk in the spare tire well and the battery mounting area.

As someone also said, pull the floor mat anchors and stick Q-tips into the holes and see if they come up wet.

I will state this AGAIN for anyone listening, if you park the car overnight and you come out in the morning and the windsheild, rear window and/or sunroof glass is fogged up on the INSIDE, there is a 99% chance there is water intrusion in the vehicle.

The only caveat is if you are talking about a very rainy day before hand and the car may have had extra humidity in the cabin due to wet coats, shoes, umbrellas and so forth, just wait a few days, if there has been no rain in a day or more and the windows are fogged up when you enter the car, there is high humidity in the car due to water intrusion.

Fogged up windows with just the driver or multiple passengers may be normal, BUT and this is a BUT, there still may be high humidity in the vehicle due to water intrusion so the cabin may fog up quicker than if the cabin was dry like it should be.

Put a humidity gauge in the car, compare the humidity inside the cabin to the local humidity, they should for the most part match or at least the interior should not typically be much higher than the outside humidity.
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Last edited by jfoj; 12-18-2016 at 03:18 PM.
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Old 12-19-2016, 06:50 AM   #15
Foxtrot_Uniform
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Originally Posted by ChadTsunami View Post
Thanks for the suggestions jfoj!

1. I can't be certain that I have factory window regulators in this car but I think may be as I have not replaced them since I got it in March 2015. Either way the door jams have always been dry after rainy days so that looks good.

2. Sunroof drains. I think this actually may be part of the issue, I'll have to investigate and report back.

3. My lower windshield cowl is actually in rough shape so this may be contributing to the problem too. I'll def replace it.

4. I recently cleaned the cabin air filter drains so this should be good to go.


I'll work on checking the sunroof drains and replacing the windshield cowl and report back when I get some good results.


Thanks again for the help!
1. listen to fjoj... He knows his sh*t!

2. Just because you have dry door jambs doesn't mean anything. Mine leak and it drops straight down from the inner door cars to the carpet... Bypassing the jamb!

This is where I'll bet you have a leak. I will guarantee that every one of your regulators has been replaced. I have replaced all mine at least once and some 2-3 times. I was a little sloppy on replacing the inner vapor barrier which led to my leaks. I have one issue left to resolve on the passenger side rear. I have a new regulator (4th one on this window) to install so I'll get it in the spring.

Curious what fjoj thinks of regularly exercising the regulators to lengthen their life. Mine tend to go bad because I don't use the windows often other than the driver's side. They tend to almost get stuck in place after staying in one position for so long. They sometimes pop open and I think that stresses the mechanism and eventually breaks it. My driver's window has been replaced only once... My theory is that it is the most used and stays free.
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Old 12-19-2016, 08:01 AM   #16
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My theory on the vapor barrier leaks is this.

1. I think the doors that get less used tend to have more problems. Water will collect near the butyl seal and cause dirt to collect. I also think during the Winter weather if any water has collected here it can freeze and start to work the butyl seal loose. If the doors are open and closes a few times after a rain or washing the car this may help matters.

2. Any repairs inside the door will cause people to pull the butyl loose and it may not be able to reseal properly. Often heat and a roller may be useful for resealing and/or new/additional butyl may need to be added.

3. As for window regulators, I do believe the glass can and will stick in the window tracks and to the rubber seals and gaskets. The initial opening is not easy on the motor, cables and pulleys. I did some testing with some Teflon spray and found it helps. The worse thing is for a car to sit with the windows up in the sun for extended period of time, this can and will cause the window to stick more. Check this thread for more comments on lube for the window tracks and gaskets - http://forum.e46fanatics.com/showthread.php?t=1079371
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Old 12-19-2016, 04:03 PM   #17
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Originally Posted by jfoj View Post
My theory on the vapor barrier leaks is this.

1. I think the doors that get less used tend to have more problems. Water will collect near the butyl seal and cause dirt to collect. I also think during the Winter weather if any water has collected here it can freeze and start to work the butyl seal loose. If the doors are open and closes a few times after a rain or washing the car this may help matters.

2. Any repairs inside the door will cause people to pull the butyl loose and it may not be able to reseal properly. Often heat and a roller may be useful for resealing and/or new/additional butyl may need to be added.

3. As for window regulators, I do believe the glass can and will stick in the window tracks and to the rubber seals and gaskets. The initial opening is not easy on the motor, cables and pulleys. I did some testing with some Teflon spray and found it helps. The worse thing is for a car to sit with the windows up in the sun for extended period of time, this can and will cause the window to stick more. Check this thread for more comments on lube for the window tracks and gaskets - http://forum.e46fanatics.com/showthread.php?t=1079371
My thoughts exactly!
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Old 03-19-2017, 06:53 PM   #18
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I find that with the first sunny mild afternoons of spring, I come out to the car in the afternoon - not first thing in the morning - and the windshield's fogged. Carpets are dry. Vapor barriers were re-sealed a couple months ago ( when I did have damp carpets). Did the q-tip test down the floor mat holes - dry as a bone. Spare tire well in the trunk, dry. Cabin air filter tray drains not clogged. Sunroof draining properly. Not losing coolant, HVAC system works perfectly. Winshield cowl in good shape.

In short I cannot find any evidence of any water in the car and figure it's the greenhouse effect in a car parked in the sun? Why aren't my other cars doing this in the same conditions?
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Old 03-19-2017, 08:05 PM   #19
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In short I cannot find any evidence of any water in the car and figure it's the greenhouse effect in a car parked in the sun? Why aren't my other cars doing this in the same conditions?
Your other cars do not have excessive moisture in the cabin. Your BMW has excessive moisture in the car you have not found.

Trust me. Just get a humidity gauge and put it in the car, compare the humidity inside the car to outside, you will see.
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Hidden OBC Menu - Check Voltage, Temp, Fuel Level - http://forum.e46fanatics.com/showthread.php?t=239619

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Lower hose temp switch O-ring - BMW #13621743299

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Old 03-19-2017, 08:37 PM   #20
tailendcharlie
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I hear you. Pretty much run out of places to look for moisture......pulled out back seat, no water there. Foam is dry. Don't know where else to look at this point.
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