Windows steaming up overnight.

[LUSKY75]

I have a 2013 c class estate, the thing is , when I leave it for a good few hours my windscreen and other windows steam up inside.
Can anyone tell.my why?
Thanks

 

[MCFastybloke]

Wet carpets?

 

[Smart320]

Blocked drains at bottom of the windscreen, as MCF suggested check carpets in footwell

 

[John]

Are all the windows all firmly shut.

Could be failed door / window rubber...

 

[LUSKY75]

Will check the windscreen drains.
Cheers

 

[MCFastybloke]

Sunroof drains too, if you have one

 

[fabes]

Wet umbrella left in car ( my wife's favourite trick)?

 

[Larkone]

Condensation from the AC unit in the heater? Possible the drains are blocked

 

[MrGreedy]

As above. Some moisture is getting in.
Go round all the carpets in the car feeling for damp, front and back, and strip all the boot floor trim out to have a look. This might help identify if it's a front or back leak.
But scuttle panel drains are a common one.

 

[Gazwould]

Also the pure physics of exiting a warm heated vehicle and parked up for the night means the glass cools down and the warm air condensates on the inside glass .

Last few minutes of a journey turn the heating to a cool setting to bring the interior temp down .

 

[SL03WLY]

Not trying to be an a'rse but have you left your ventilation to recirculate? Also have you changed your Pollen Filter anytime recently?

 

[Gbrowncls55]

Possibly an a/c fault. When my ac failed the windows steamed up really badly. New condensor solved it. more likely a blocked drain. Oddly I have literally just finished clearing out all the drains on my wifes SL R230 as she has exactly the same issue

 

[chesterpiglet]

If it persists then you have a problem but I am with Gazwould & it may be down to warm humid air trapped in the car that then condenses when the glass cools down overnight. I had the same problem last week but now all fine.

 

[Gazwould]

Not trying to be an a'rse but have you left your ventilation to recirculate? Also have you changed your Pollen Filter anytime recently?

I share that view but recently a veteran VAG indi claims the opposite .

"Taking the air from inside the car rather from outside, then passing it through the evaporator, causes moisture to condense on the evaporator; this builds up until droplets are formed which drain down to the collector sump under the condenser. This water is then exhausted via the condensation drain pipe, not only by gravity but by the positive air pressure within the HVAC system generated by the blower fan. The now drier air is then blown back into the cabin and the process is repeated so drawing more moisture out of the interior not just from the air itself but deep down from absorbent materials by wicking."

 

[SL03WLY]

I share that view but recently a veteran VAG indi claims the opposite .

"Taking the air from inside the car rather from outside, then passing it through the evaporator, causes moisture to condense on the evaporator; this builds up until droplets are formed which drain down to the collector sump under the condenser. This water is then exhausted via the condensation drain pipe, not only by gravity but by the positive air pressure within the HVAC system generated by the blower fan. The now drier air is then blown back into the cabin and the process is repeated so drawing more moisture out of the interior not just from the air itself but deep down from absorbent materials by wicking."

hmmm thats interesting. Never would've thought of it like that but heck the indi's statement makes sense to me.

 

[W1ghty]

Are you doing a decent length drive , with aircon on all year ? Has this just started happening

 

[Gazwould]

hmmm thats interesting. Never would've thought of it like that but heck the indi's statement makes sense to me.

Only one thing left to do...

 

[DubMerc]

Is there a useful how to video or instruction on how to clear or check if drains are clear? Don't have this issue at the moment but would like to know how to diy it if/when I do.

 

[SL03WLY]

Only one thing left to do...

Find the Indi and water board him so the info doesn't get out?

 

[OneForTheRoad]

Is there a useful how to video or instruction on how to clear or check if drains are clear? Don't have this issue at the moment but would like to know how to diy it if/when I do.

I find that a full kettle of boiling water and a squirt of washing up liquid gets them clean.