Foggy windows during rain - no solution?

[RicardoM]

It is my turn to ask for advice. I am clueless. Out of ideas.

 

Who?: Any local Skoda Felicia w/o air conditionong. But there are plenty of topics in European forums too. No working solution so far.

When?: During rain, lower outside temperatures (5-15 C)

What?: Heavy fogging on all windows. The blower/ matrix heater are operational but don't help much. Moreover, if the car is parked in an underground parking lot at a mall after a rain, the windows get all white from condensation by the time we return from shopping. You can see a sea of cars parked with clear windows and here and there all fogged up Felicias

Tried w/o success: defogger spray, silica gel pouches, shaving cream, toothpaste (yeah, I know...)

 

From my experience, there are certain car models more prone to windows fogging than others. I can't tell for sure why that happens. My best guess is a design flaw of the ventilation and air circulation.

 

If you know any verified tips (including on other car models) please share. You will have my gratitude.

[Web Ferret]

Cars have single glazing. Simple physics say cold suface = condensation.

 

Some 1kg silica gel bags will absorb the moisture. Look up on amazon.

 

Holy grail is a heated garage.

[Tech1e]

Don't drive in the rain?

[trundlenut]

Are all the carpets dry? Plus the spare wheel well?

Had an astra like this, boot carpet was soaked and wheel well was full of water. Mainly due to people leaving the boot open all day in the rain.

Sent from my D5803 using Tapatalk

[daverapid]

Fancy asking for help, you never help anyone else!!  Only joking!

 

Windscreen leaks are common on these.

[felicia16v]

Windscreen leaks badly also check the heater box drain as they block up and water then gets drawn into the heater itself.

Clean all the glass with good glass cleaner too.

[StevesTruck]

Find where the moisture is getting in. Stop it getting in, then take your interior out and dry it out.

[RicardoM]

Thank you all for replies.

I had to disregard the advice of not using the car when it's raining for obvious reasons. If people in the UK would drive only when the sky is clear, it would be just two to three days of traffic per year.

 

But the rest of replies hold true and are useful. I will summarize them as follows:

• new moisture enters into the cabin as:

1. humid air or
2. as liquid (windshield leaks, bad door seals, wet shoes, wet clothes, etc.)

• there is also old moisture in upholstery due to the foam underneath
• drain holes could be plugged (in the blower housing, doors, tailgate, front wings, engine bay, rear arch wheel)

Speaking of door drain holes, I've just realized something common to all local Felicias. Every owner had to remove the door panel cover at one time for various reasons. On that occasion the clear plastic sheet known as "moisture barrier (!)" was ripped off and never replaced. Am I right thinking that was a mistake?

 

One other question for you. The moisture that enters in liquid form into the cabin has to evaporate to get into the air and then condensate on windows. It seems to me that there is not enough heat in the cabin to evaporate the liquid. Am I right?

 

It also seems to me the biggest source of humidity is the blower/heater combination. The heat of the heater vaporizes and heats the humid air which then foggs the windows big timr. Is this reasonable?

 

One other unknown for me. How should the air circulate in the cabin? I know the entries, but where are the vents for letting bad air escape out? Is there such thing as natural in-out air circulation for Felicia? Because without vent out, the cabin is a sauna...

[ehabmobarak]

I found this video 

https://youtu.be/8Vj9avZxuwI

also this

https://youtu.be/ZIR2uO3SpZg

I hope it helps

[RicardoM]

I found this video 

https://youtu.be/8Vj9avZxuwI

Oh yeah... good ol' ChrisFix... I know that video and also the sequel to it. But as I mentioned in my first post, shaving cream and toothpaste didn't work. Chris probably works in marketing. If not, he should. He could sell sand to Arabs or ice to Eskimos. He is a major BSer.

 

also this

https://youtu.be/ZIR2uO3SpZg

I tried better than salt. Silica gel in a sock. No luck either. By the way, somebody should tell the uploader of the video that he has the luxury of having A/C recirculation...

 

Thanks anyway, Ehab.

[HeavyMetalRich]

Hi Ricardo,

 

There are a couple of drain holes in the aperture for the windscreen that could be bad for clogging. You'll only see them with the screen out, I've had mine enlarged to prevent clogging. Otherwise there is the fact that the seal isn't bonded and the rubber moves and shrinks. Also your idea about the door membrane would be worth looking into as well. it wouldn't take much to sort either, just cut a piece of decent plastic and stick it on with silicone.

 

You would be right about the water not being able to escape. The best indicator is the foam under the dash board, above your feet. This is usually wet if your windscreen is leaking. The heater is more than capable of drying it out though. A good long run with it on should dry out the foam. However that brings you back around to how to disperse the moisture...

 

I would suggest driving with the window open helps (provided it isn't raining again of course!). Again on nice hot days (if you see many of them this time of year) leave the windows open slightly or even better, the doors provided you're parked in a safe place where your car isn't going to be stolen or raided. For the carpet, Steve'sTruck's suggestion of removing the interior is your best bet. Use the wet vacuum cleaner to get out as much moisture as you can and leave it somewhere warm to air.

 

Sorry if this all sounds too obvious or patronising but its all tried and tested.

[RicardoM]

Thanks Rich. The first thing I will try is vacuuming thoroughly any moisture from inside the car (carpets, upholstery) as Steve and you suggested. Although I am quite reluctant. It's this little thing bugging me: how could water in liquid form vaporize from the carpets and upholstery ?? You need quite a lot of heat for that.

 

On the other hand, although it was mentioned as a possibility, my car or any other local car I've seen has no windshield leaks, and I've seen quite a few. Never felt wet foam under the dash on any Felicia.

[KenONeill]

First off, removing "moisture barrier" sheets from doors is always a mistake. Yes, doors do have drains at their bases, but the water gets in at the rubber strip on the base of the winding section, and tends to lie in the door until the car is next driven at highway speeds. That membrane is all that stops it getting to the interior.

 

Next, following from that, check the holes in the door bases are clear so that the water in the doors can drain out! This is more of an issue if the car is sometimes used on mud or gravel.

 

Third, from experience, if you don't have working air con, demist the car with the heater set on cold.

 

Fourth, check that any drain holes in the ventilation intake, and in the mixer plenum, are clear,

 

Fifth, if applicable, check that any one way valves in cabin air extract ducts work.

 

Finally, and this can very from year to year and with whether or not you have one, check that the pollen filter is reasonably new and dry (or removed if you don't suffer from hay fever).

[RicardoM]

Before vacuuming the interior I decided to install a DIY moisture trap similar to that in the video below, except much cheapar using household objects and cat litter as desiccant.. I will let it sit on my central console till next weekend. Let's see how much moisture (if any) will collect the contraption.

 

This morning I've removed all door panels and I've installed the plastic sheets back. I've found one clogged drain on passenger's door.

 

Edited 7 March, 2016 by RicardoM

[pinjon]

I have your same problem but i think it's water leaking related. At least it always happens on heavy raining days. On sunny days even if it's cold it doesn't.

On mine it's not that bad. Full heating and fan on 1. gear always clears the front windscreen.

Does your stay foggy even on heating it?

I was thinking on the same route as you about vent holes. Ended up leaving a window open for half a cm for that reason (to help pushing wet air out) but can't say it helped clearing windows in the cabin any faster but it didnt make it worse too.

I still have all plastic sheets on all doors and foggy glass anyway.

 

I know that I have a small water leak on the boot door (can't find the reason) and that's a major factor for foggy windows. A small amount of water in the boot makes my interior looking like a sauna. ;-)

[HeavyMetalRich]

Thanks Rich. The first thing I will try is vacuuming thoroughly any moisture from inside the car (carpets, upholstery) as Steve and you suggested. Although I am quite reluctant. It's this little thing bugging me: how could water in liquid form vaporize from the carpets and upholstery ?? You need quite a lot of heat for that.

 

On the other hand, although it was mentioned as a possibility, my car or any other local car I've seen has no windshield leaks, and I've seen quite a few. Never felt wet foam under the dash on any Felicia.

 

The amount of vacuuming required should be significantly reduced by your home made de-humidifier. Please report back as to how well this works, I'm interested to know.

 

You'd be surprised at how little heat is needed to start evaporating the damp. Obviously it needs to be much higher to get rid of all the water but it does help a little. And if you're doing it continually it will add up.

 

The fact you have no windscreen leak is a big plus.

[RicardoM]

I was thinking on the same route as you about vent holes. Ended up leaving a window open for half a cm for that reason (to help pushing wet air out) but can't say it helped clearing windows in the cabin any faster but it didnt make it worse too.

Leaving a window open doesn't vent the humidity. It only cools the air inside and reduces the chance of condensation by equalizing the temperature of the windows and of the air inside. IIRC air humidity 'travels' only from humid, saturated areas to dry areas just like heat 'travels' always from hot areas to cold areas. During rain, outside air is saturated so humidity will go higher inside the car.

 

I know that heating and ventilation of the interior of a car is part of the overall design process. A team of experts does extensive tests for having efficient and confortable air flow through the cabin. There must be air vents (usually in the back of the car) to help creating a flow of air from front to back. But I didn't see an illustration made by Skoda showing it. The only air vents(?) I know are on the rear side of the rear doors, but I'm not sure how they are supposed to work.

 

[HeavyMetalRich]

On other models I have noticed vents that exit at the bottom of the rear quarter panels, behind the rear wheels and are covered by the bumper. Does anyone know off hand if the Felicia has these? It would be interesting to know if they are used or if Skoda thought the ones in the doors, as shown by Ricardo, would be enough. I can't say I've paid much attention to a Felicia with its rear bumper off.

[RicardoM]

I didn't see any vent behind the rear bumper. As for the vents (?) in the rear doors, they vent the inside of the rear doors ?? Why?

There must be some kind of vent for vehicles without A/C, I think. Not sure if that is true for cars with A/C. Logic tells me A/C cars have a 'sealed' interior with controlled vents to get rid of CO₂.

[felicia16v]

No im pretty sure the only vents are those in the doors. The plastic membrane has a few holes covered with flaps to let air thru and water out. I dont think there is any changes to that for ac cars either.

[StevesTruck]

Thanks Rich. The first thing I will try is vacuuming thoroughly any moisture from inside the car (carpets, upholstery) as Steve and you suggested. Although I am quite reluctant. It's this little thing bugging me: how could water in liquid form vaporize from the carpets and upholstery ?? You need quite a lot of heat for that.

 

Kinetic theory says all molecules in a liquid are moving, some will break surface tension and become airborne moisture- it's how clouds work as well

 

If you can't work out where the water's getting in, take as much of the interior out as you can, chuck a seat back in to drive about and wait for it to rain, you'll see it trickling down somewhere.

 

Wet vacing the carpet only works to an extent because the soundproofing under it is basically a sponge, so it will be soaked. When you've the leaks stopped. Bin the soundproofing and get some new stuff under. Jet wash the carpet and hang it up to dry.

 

I gave up trying to plug the leaks in the pickup, the only way I could stop it misting was leaving the windows down an inch or two at night, I put some wind deflectors on to hide this for security reasons.

Edited 9 March, 2016 by StevesTruck

[RicardoM]

Kinetic theory says all molecules in a liquid are moving, some will break surface tension and become airborne moisture- it's how clouds work as well

I am quite sure 'kinetic theory' has nothing to do with evaporation. But a fraction of the molecules in a liquid have enough heat energy to escape into the air. For the rest of the mollecules to evaporate a lot of heat is required (from the sun or artificial sources).

 

Coming back to earth, more precisely inside Felicia, from all replies given here and on other forums I understand the air moisture comes from:

• evaporation of leaked water from body sealing defects
• evaporation of moisture in upholstery and carpets
• evaporation of water carried on shoes and clothes
• respiration
• perspiration

But to me the bulk of the air moisture is the blowe-heater combination itself. During rain, outside air (humidity saturated) passes through the heater matrix and it is blown inside as hot humid air, the worst combination for existing cold windows. There is no humidity trap whatsoever. A major design flaw. Add to that another design flaw, an inefficient natural ventilation of the cabin. I don't see how the inside air could pass through the rear door panels to vent outside.

 

Humid air adds stress to all car occupants. See Air Conditioner in the Motor Vehicle.

How can we fix those design flaws on Felicia w/o A/C ? I know, install A/C, but please stay focused.

[felicia16v]

You need to strip the carpet out and the underlay too. The main leaks are around the windscreen. I cant do pictures because im on my phone but with the screen out you can see 2 small channels that are the water drains from around the screen apature. These are too small and also not quite in the right place so we used to remove the screen and drill 3 holes along the bottom of the appature on the outside of the seam so any water that gets begind the rubber can drain down the engine side of the bulkhead instead of building up and passing over the seam and into the car..

Ive probably not explained very well so if you find a pic of a felly with the screen out ill edit it to show.

[RicardoM]

This is the best photo I could come up with.

[HeavyMetalRich]

You need to strip the carpet out and the underlay too. The main leaks are around the windscreen. I cant do pictures because im on my phone but with the screen out you can see 2 small channels that are the water drains from around the screen apature. These are too small and also not quite in the right place so we used to remove the screen and drill 3 holes along the bottom of the appature on the outside of the seam so any water that gets begind the rubber can drain down the engine side of the bulkhead instead of building up and passing over the seam and into the car..

Ive probably not explained very well so if you find a pic of a felly with the screen out ill edit it to show.

 

This is what I mentioned in my first post. Ricardo stated his screen had been sealed/does not leak. Is it possible these can flow over with the screen sealed?