Condensation inside Fron windscreen

amen

might be the wrong forum. Driving a 99 Passat. Over the last week or so I have very heavy condensation on the inside of the windscreen. The heater can't shift it.

Tried car window cleaners for inside. Don't make much difference. It is like there is fine dirt/grease on the window. Only started with the cold weather.

Any ideas on how to shift it ?

shedweller

My first thought was a leak somewhere, but given the recent rain it may just be from a door being open just long enough to let in enough rain to cause this condensation.
So, first it needs to be cleaned off. If it's water then it should mostly wipe off with a towel. Then dry it with kitchen towels. At this point you should see how much underlying dirt is on the glass. Use glass cleaner and a lint free cloth to clean it if it needs.
If it's something other than water then it gets trickier i suppose! You'll need to find out what it is. It could be evaporated coolant from a leaking heater core.....:(. Heres hoping thats not the case eh!

Then make sure you have your ventilation set to fresh air in, NOT recirculate.
Set the fan on the number one setting or higher, NOT off as this doesn't let in enough air to keep the windscreen mist free.
I often see cars (even new ones!) with completely fogged up windows and the cause is having the fan off, on recirculate and the vents closed for good measure! It's a submarine!!:pac:
I carpooled with a lad once and this was his ventilation setup. Nearly ended up in the ditch a few times too many. And there was no talking to him!
Good luck!

stimpson

Go to a glaziers. Get a can of professional cleaner. You should get a huge can for about a fiver. Clean windscreen according to instructions. Then do it again. Then breathe on it again to see where the condensation sticks. Clean this bit again. When you can't get it to fog up. Once it's immaculately clean you're sorted. Then leave it and never touch it with anything again. I used to do this once a year on my 20 year old Honda. Even on the coldest morning the windscreen would be crystal clear without using the blower.

stevenmu

Or a mix of vinegar and water, spray onto windscreen, leave a few seconds and wipe off with newspaper.

Btw, do you smoke in the car? I think this can leave a thin film like this in the inside of the windscreen.

Balbriggan mechanic

If none of the above solutions help it's probably your heater matrix. Have had to replace quite a few of these over the years on 3B model passats. Takes about 6 hours to do as the entire dashboard has to come out to do the job.

dr.fuzzenstein

Every time I had the problem of fogged up windows that no amount of heat/fan could shift it has always been down to a puddle somewhere.
In most cases under the carpet and under the seat in some hard to reach place.
Well worth crawling through the car and feeling every bit of carpet for damp, also under the seats.
If you can, check underneath the carpet, because even if the carpet feels dry, there could be water under the thick underlay.
This is usually the problem.
And of course fan needs to be set to 1 or 2 at all times with moderate heat, vents open and set to fresh air.
How anyone can have it otherwise is beyound me, your car turns into a swamp.

biko

Yeah, for many people the fan seems to be a novelty. I been in plenty cars in winter where fan was off and whole car fogged up.
And the driver was using his bare hand to wipe the wind shield, smearing it up even worse.

Stovepipe

Hi there,
I had two issues with Passats, one a pre-99 and the other a 99 estate.The older one used to have a persistent puddle in the passenger footwell, which was eventually traced to a faulty window rubber, which allowed water to run down the door and into the footwell.I resealed the rubber and that was that. I also had to change the waterlogged piece of carpet.On the older one, I had the persistent foggy windscreen and no combination of heater settings would shift it except on max blower, which is annoyingly noisy.Until a mate mentioned the pollen filter, which is under the bonnet, at the back, under the lip(valance?) above the bulkhead in a slim plastic container.I pulled it out and found the filter soaking wet.I also found the area around the wiper arm motor clogged with leaves and stuff so I cleaned that out.I changed the filter and the windscreen was always clear thereafter.I had to change the filter once more until I sold the Passat on.
regards
Stovepipe

amen

thanks for all of the posts.

I think its my heater. Occassionally when I turn it on a vapour comes out. Not nice smelling at all.

I was just checking the air in take to make sure it was taking external air and that seems to be not working correctly either.

Anyone know what sort of price to replace? Car has 166,000(got it at 40,000) miles on it but apart from the heater is sound(NCT for 2 years ) and I was hoping to keep driving till it fell apart.

audismelly

pollen filter?

itarumaa

All the details informed points to heater matrix,

specially the vapour.

Heater matrix is usually hidden inside the dashboard and it is pain to change.

Piri

Check the drain below wipers
It should be blocked by leaves

saltcoats

hoping to keep driving it till it fell apart....
maybe it is now falling apart 166000 is a lot of miles.
and don't anyone be saying thats not a lot for a passat it is .
it's a car not a starship.
anyway my 520i is giving me similar problems hard to clear misting, i have been opening the window just a tad and when the fan decides to kick in it clears the window not ideal in this weather but it works

amen

well apart from the heating everything is sound, body fine ( no rust), engine fine. Apart from new brakes and timing belt change (twice) I haven't really spent much on it.

Piri

saltcoats wrote: »

hoping to keep driving it till it fell apart....
maybe it is now falling apart 166000 is a lot of miles.
and don't anyone be saying thats not a lot for a passat it is .
it's a car not a starship.
anyway my 520i is giving me similar problems hard to clear misting, i have been opening the window just a tad and when the fan decides to kick in it clears the window not ideal in this weather but it works

Every inspection need to clear drain holes under pollen filter
Nobody doing this

Matt Simis

Balbriggan mechanic wrote: »

If none of the above solutions help it's probably your heater matrix. Have had to replace quite a few of these over the years on 3B model passats. Takes about 6 hours to do as the entire dashboard has to come out to do the job.

I would try Novastop additive before the full on Dash removal, tried and tested myself, works excellent. Costs EUR20 and 10min.

Supercell

Had the exact same thing, was the heater matrix. Expensive to get replaced too, sorry OP if its that.

Balbriggan mechanic

Had a look through some of the posts after mine and one of them rang a bell with me. The pollen filter housing on the passat is known to leak if the drains in the scuttle get blocked. If you open the bonnet and look up on the lh side under the windscreen you'll spot the pollen filter. If you remove it and it's wet the housing is probably leaking water down into the heater box. If you remove the plastics that cover the scuttle you should be able to fully access the housing. It's held in place by 2 or 3 plastic M6 nuts. unscrew the housing and check the foam seal underneath. If it crumbles in your fingers it needs replacing. You can buy a strip of this seal from VW for about a fiver or for a better job get some windscreen sealer from the motor factors. Seal the bottom of the housing and replace. Make sure to clean the drains on both sides of the scuttle with a wire hanger or something similar while you're there. You won't know for a couple of weeks if it's worked as there is no easy way to completely dry out the inside of the heater box. If a water leak is the problem it will need to be sorted quickly before dampness reaches the comfort control module under the passenger seat. Both this and it's wiring loom are very suceptible to water damage. This if damaged by water will cause all sorts of problems with central locking, electric windows, sunroof etc. Hope this helps:)

OYAD666

HAVING THE SAME PROBLEM IN 08 TOYOTA AURIS CAR HAS BEEN STRIPPED OUT INSIDE LOOKING FOR WATER OR A LEAK FOUND NOTHING CAR IS CLEAR DURING SUMMER BUT HAS STARTED TO FOG UP AGAIN WHEN IT GETS FROSTY THE INSIDE SCREEN HAS ICE ON IT.BEEN BACK TO THE GARAGE SERVERL TIMES MADE NO DIFFERANCE.TOYOTA TOLD ME IM NOT DRIVING THE CAR ENOUGH FOR IT TO GET HOT ENOUGH TO CLEAR THE SCREEN BECAUSE ITS A DIESEL.TO ME THIS IS A LOAD OF BULL....DRIVING A HIACE DIESEL BUT DONT HAVE THIS PROBLEM.....ANYBODY HAVEING THIS PROBLEM????/

BostonB

Please don't use caps is really hard to read. An 08 car shouldn't be having problems like that with condensation. Find a better garage/mechanic.

shedweller

OYAD666 wrote: »

HAVING THE SAME PROBLEM IN 08 TOYOTA AURIS CAR HAS BEEN STRIPPED OUT INSIDE LOOKING FOR WATER OR A LEAK FOUND NOTHING CAR IS CLEAR DURING SUMMER BUT HAS STARTED TO FOG UP AGAIN WHEN IT GETS FROSTY THE INSIDE SCREEN HAS ICE ON IT.BEEN BACK TO THE GARAGE SERVERL TIMES MADE NO DIFFERANCE.TOYOTA TOLD ME IM NOT DRIVING THE CAR ENOUGH FOR IT TO GET HOT ENOUGH TO CLEAR THE SCREEN BECAUSE ITS A DIESEL.TO ME THIS IS A LOAD OF BULL....DRIVING A HIACE DIESEL BUT DONT HAVE THIS PROBLEM.....ANYBODY HAVEING THIS PROBLEM????/

Caps are a PITA. But do check your ventilation settings as per my earlier post. No fresh air in means foggy windows. Rod and back spring to mind!!

amen

I've tried the pollen filter seems ok.

Thinks its something else :-(

highlydebased

Must try the professional window spray. Mine usually has condensation- takes about 5 minutes to clear with fan.

Drives me nuts when people refuse to have the fan even on the lowest setting whilst idle- some preconcieved notion it quadruples their petrol usage or something silly.

OYAD666

all vent set to fresh air car was total strip out and i mean total back to metal & wires no water all vents out heater out all checked screen.checked for leaks with running water for 2 hrs. car left running for 3 hrs with heat on full and windows open a crack for vent circulation still not fixed.dehumidfier put in car for 6hrs next time still condensation build up on cold mornings

BostonB

Check the door linings aren't ripped or holed, and the drain holes in the door.

Check train holes in sunroof, if you have one.

OYAD666

will check that this week thank u.

BostonB

Had an old fiesta and taped up bin bags into the doors to replaced the torn liners. Improved it a lot. But it could be anything tbh. On some VW's theres some plugs behind the pedals through the bulkhead that come out causing a leak/damp.

A lot of garages/mechanics won't touch these kinda issues, as they are so time consuming to find. A bit of patience and time, and you'll eventually find it.

antodeco

Have the exact same issue on an 06 Almera. The inside of car itself feels damp, but I checked all the rubber seals and it seems ok.

OP, as silly as this may sound, check the water hoses for your window sprayers. Sometimes they leak going from front to the back window. If its leaking, that could be your issue too..

dr.fuzzenstein

OYAD666 wrote: »

HAVING THE SAME PROBLEM IN 08 TOYOTA AURIS .....ANYBODY HAVEING THIS PROBLEM????/

Had a problem like that with a 99 Focus estate.
Completely removed the interior, crawled underneath everything with a light whilst garden hose sprinkled car, removed all door cards, half the dash, pollen filter housing, put about 5 kgs of silicone into car, removed headlining, all interior trim, no good.
Sold the car, bought a better one, problem fixed!:D

OYAD666

Thanks doc thats my next move maybe in new year:D