Large amounts of condensation on the inside of the windscreen.

[CallumFox5]

I have a 4 year old Seat Leon FR and the past month or so I have discovered on some occasions the inside of my windscreen gets a really bad case of condensation, and never any on the outside of the window.

I have tried to use the heating controls to demist it but when you need to get going to somewhere this can take a bit of time.

I tried to wipe it away the other night and that left horrible marks when I wiped it away it became more like water and I had no cloths to wipe it up so driving at night with horrible smear marks isn't fun.

I was just wondering if anybody else had issues with it.

 

[Adrian300]

Usually condensation on the inside is due to a water ingress into the car. Have u checked footwells, spare wheel wells for signs of water ingress? Wet shoes can sometimes cause it when getting in the car which inturn makes the mats wet but it sounds worse than that.

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[Legojon]

Also, I know this sounds weird... but I cleaned the inside of the windscreen with a clay bar followed by white vinegar. That helped quite a bit having a completely clean windscreen. If it's still bad you can apply something like this:
https://www.cleanyourcar.co.uk/gyeon-q2-anti-fog

 

[CalJames]

I recently had really bad condensation, turned out my car was letting in water in the spare wheel well. There was a leak behind the rear bumper, some vent had broke.
Whilst getting it repaired, the service department at Seat advised me to help reduce condensation, just before leaving your car turn the blower to feet and leave it a few seconds. Something about helping the windscreen cool faster.

 

[LouG]

I've always used the demist setting for A/C. Condensation is just warmer moist air hitting a cold screen, warm the screen and the condensation goes. Just like in the bathroom.

 

[Adrian300]

Yeah agree, do you use your air con in this weather as it also acts as a dehumidifier. Just use it on a hot setting.

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[SRGTD]

Lots of discussion threads like this on many forums at this time of year, every year, I’ve always kept my A/C on 24/7 and never had issues with condensation build up - at most, just a small amount of fogging that clears as soon as I start the engine. I’ve assumed the dehumidifying effect of the A/C is what keeps the moisture at bay.

As @Adrian300 has said, excessive condensation in the car is usually the result of water ingress.

@CallumFox5; check to see if your mats or carpets are damp as it could be an indication that water is finding it’s way into the cabin. Also check the spare wheel well in the boot for water, and if you have any damp outside clothing or wet umbrellas in the car, remove these items from the car.

Possible causes / things to check below. These items have been reported by mk7 / mk7.5 Golf owners on various forums. Some or all of these might also affect the Leon, so worth checking.

• Blocked pollen filter. I had this many years ago in a non-VAG car and it was almost impossible to see out of the windows because of the excessive condensation build up!
• If you have a sunroof, blocked sunroof drain pipes can result in water draining into the car.
• Damaged / broken door speaker seals/gaskets seems to be an issue on some mk7/7.5 Golfs, resulting in water getting into the cabin past the defective speaker seals/gaskets.
• Damaged / poor fitting door or window seals.
• Damaged / perished drain grommet on the bottom of the tailgate. Reported on some VW forums. If the grommet is damaged / perished, the bottom end of the drain pipe from the tailgate handle / VW badge is loose inside the tailgate and water can drain from the tailgate into the boot.
• Damaged or perished seal(s) between the rear light clusters and the car body.

If any of the following are the cause of water ingress, then it’s likely the headlining at the rear of the car will be either damp or water stained;

• Damaged / cracked ribbed rubber sleeves covering the wiring from the top of the tailgate opening into the tailgate, or a poor seal between the rubber sleeve and bodywork.
• Poor seal between the tailgate hinges and where they’re attached to the body shell above the tailgate opening - a problem on some early mk7 Golfs.
• Damaged/perished rubber washer / gasket between the roof and roof mounted aerial.

 

[Adrian300]

Also to add if a washer pipe that runs to the rear has popped off if it was frozen, this can also cause water/washer fluid into the cabin.

I also use my ac 24/7, and i have never had any ac issues on any of my cars. The ac gas actually acts as a lubricant to keep all the seals in the system lubed. As a lot of failures/leaks are when these seals harden up and perish.

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[Copra68]

Change the pollen/cabin filter unless you know its been changed recently. They are cheap enough to change once a year.

 

[BigJase88]

My brand new FR had this issue last year. Seat could not find a leak and gave me a service bulletin from 2014 blaming things like the dewing point of water

so it is a known issue

 

[CallumFox5]

Thanks for all the replies.

I'll check the spare wheel well. And change the pollen filter, see if that changes anything. There's no consistency to when this occurs which makes it harder to work out why.

 

[andycupra]

do not wipe the screen and leave the wet rag in the car and expect a clear windscreen.

its all about relative humidity, - you will drive the car with heating on, breathing and maybe with wet clothes leaving a warn high humidity cabin. as the temps drop you get condensation as lower air temps can hold less moisture.
When you are nearly at your destination, turn the heating off and let it run cold and open a couple of windows to give the cabin a clear out (hopefully with colder air with a lower relative humidity).
as mentioned using the air con with dehumidifier is another option.

Sadly its a natural occurrence, difficult to eliminate but if you are aware of what can raise moisture levels in the cabin you can improve things alot.

 

[DrEv1l]

When I had my windscreen replaced the tech suggested to keep some silica gel packets that you get from some food containers in the car. They suck up the moisture. Also I used a dehumidifier aero 360 in one of my old cars that was sitting on the drive for a while and did defiantly leak like an old sieve. It helped keep things dry and smelling ok until it was bought.

DrEv1l.