Condensation inside car

blunderthumbs

Active member
 Cheshire
Anyone else have this :? . Have just been out to the Zed and there's condensation inside at the top of the Windscreen. :( Carpets and everything else dry as a bone.
 
I try not to give mine a chance to build up condensation.

I use a couple of dehumidifier bags. Just rotate them around. Seems to do the trick
 
Bmwforachange said:
I try not to give mine a chance to build up condensation.

I use a couple of dehumidifier bags. Just rotate them around. Seems to do the trick
Where would I get these from please :roll:
 
Stacks of them on Amazon https://www.amazon.co.uk/Simply-DEH001-car-Reusable-Dehumidifier/dp/B07L9NWY1N/ref=sr_1_5?crid=3TTRWQNFVNXKR&dchild=1&keywords=hoomee+silica+gel+car+dehumidifier+bag&qid=1612125541&sprefix=hoomee%2Caps%2C234&sr=8-5
 
mr.tourette said:
Stacks of them on Amazon https://www.amazon.co.uk/Simply-DEH001-car-Reusable-Dehumidifier/dp/B07L9NWY1N/ref=sr_1_5?crid=3TTRWQNFVNXKR&dchild=1&keywords=hoomee+silica+gel+car+dehumidifier+bag&qid=1612125541&sprefix=hoomee%2Caps%2C234&sr=8-5
:thumbsup:
 
I had exactly that issue on my 'new to me' E85.
One thing I noticed, or the wife did, was that the roof was soaking through. She could feel it wet in the liner.
Got the hood waterproofed and a couple of these https://www.amazon.co.uk/ANSIO-Interior-Dehumidifier-Condensation-Dehumidifiers/dp/B01C6V5IVG/ and it's been much improved.
Not 100% dry yet, but I'm hoping some warmer days blasting with the roof down will help.

Was good to see the heavy rain just beading on the roof though, that made a huge difference
 
JayUK said:
I had exactly that issue on my 'new to me' E85.
One thing I noticed, or the wife did, was that the roof was soaking through. She could feel it wet in the liner.
Got the hood waterproofed and a couple of these https://www.amazon.co.uk/ANSIO-Interior-Dehumidifier-Condensation-Dehumidifiers/dp/B01C6V5IVG/ and it's been much improved.
Not 100% dry yet, but I'm hoping some warmer days blasting with the roof down will help.

Was good to see the heavy rain just beading on the roof though, that made a huge difference

OP; given that you get condensation from hot damp air cooling (the top of the windscreen being further away from the blowers and therefore the coolest bit) ask your self why have you got hot damp air.

OK its very humid at the moment ... rain isn't the worst form of humidity very often the ground dries quickly after rain as the wind evaporates any water on the surface but at the moment the air has a lot of trapped water and the saturated ground or melting snow are a ready source for more. This time of year more than summer its important to run your air con to get hot dry cabin air - AC is not just for cool air in summer!

I know cars are vented but most seal well enough that if you park it dry it stays dry. Of course if its wet - damp carpets; seats etc if the sun gets on it the air warms - hot damp air rises and at night condenses onto the coldest bits which is the glass and then the fabric hood.

JayUK. The Z4 hood has a water proof membrane - no need to seal the fabric of the roof although many do - I would look for water ingress somewhere else - the drains off the back of the hood will fill the body cavities behind the doors. Not only will this drown your roof motor it vents (warm damp air on a sunny day or with the heating on full) into the cabin. You can see the gaps with the roof down and any build up of water. I would check the drains are clear and you've no standing water. Also look in the boot in the battery well and feel round the rear light clusters this seems to be another common leaking point.
 
Crazy Harry said:
JayUK said:
I had exactly that issue on my 'new to me' E85.
One thing I noticed, or the wife did, was that the roof was soaking through. She could feel it wet in the liner.
Got the hood waterproofed and a couple of these https://www.amazon.co.uk/ANSIO-Interior-Dehumidifier-Condensation-Dehumidifiers/dp/B01C6V5IVG/ and it's been much improved.
Not 100% dry yet, but I'm hoping some warmer days blasting with the roof down will help.

Was good to see the heavy rain just beading on the roof though, that made a huge difference

OP; given that you get condensation from hot damp air cooling (the top of the windscreen being further away from the blowers and therefore the coolest bit) ask your self why have you got hot damp air.

OK its very humid at the moment ... rain isn't the worst form of humidity very often the ground dries quickly after rain as the wind evaporates any water on the surface but at the moment the air has a lot of trapped water and the saturated ground or melting snow are a ready source for more. This time of year more than summer its important to run your air con to get hot dry cabin air - AC is not just for cool air in summer!

I know cars are vented but most seal well enough that if you park it dry it stays dry. Of course if its wet - damp carpets; seats etc if the sun gets on it the air warms - hot damp air rises and at night condenses onto the coldest bits which is the glass and then the fabric hood.

JayUK. The Z4 hood has a water proof membrane - no need to seal the fabric of the roof although many do - I would look for water ingress somewhere else - the drains off the back of the hood will fill the body cavities behind the doors. Not only will this drown your roof motor it vents (warm damp air on a sunny day or with the heating on full) into the cabin. You can see the gaps with the roof down and any build up of water. I would check the drains are clear and you've no standing water. Also look in the boot in the battery well and feel round the rear light clusters this seems to be another common leaking point.
Thanks for your response. However the car has been parked for a few days. I check the carpets and boot regularly and they are as dry as a bone. Have checked again this morning and still the same. I slipped my hand behind the roof lining to feel for any dampness and towards the front of the roof my hand came out a bit wet. It's not saturated but moist shall we say. Maybe I will get a couple of those De-Humidifying bags that "bmwforachange" recommended. Do not really want to seal the roof with the likes of Fabseal as I have read the comments on the forum regarding the Butyl membrane etc. :?
 
Check the seals etc as mentioned above. Water is getting in somewhere for it to condense inside, so thorough checkover and big bags of silica to dry out properly afterwards.
 
blunderthumbs said:
Crazy Harry said:
JayUK said:
I had exactly that issue on my 'new to me' E85.
One thing I noticed, or the wife did, was that the roof was soaking through. She could feel it wet in the liner.
Got the hood waterproofed and a couple of these https://www.amazon.co.uk/ANSIO-Interior-Dehumidifier-Condensation-Dehumidifiers/dp/B01C6V5IVG/ and it's been much improved.
Not 100% dry yet, but I'm hoping some warmer days blasting with the roof down will help.

Was good to see the heavy rain just beading on the roof though, that made a huge difference

OP; given that you get condensation from hot damp air cooling (the top of the windscreen being further away from the blowers and therefore the coolest bit) ask your self why have you got hot damp air.

OK its very humid at the moment ... rain isn't the worst form of humidity very often the ground dries quickly after rain as the wind evaporates any water on the surface but at the moment the air has a lot of trapped water and the saturated ground or melting snow are a ready source for more. This time of year more than summer its important to run your air con to get hot dry cabin air - AC is not just for cool air in summer!

I know cars are vented but most seal well enough that if you park it dry it stays dry. Of course if its wet - damp carpets; seats etc if the sun gets on it the air warms - hot damp air rises and at night condenses onto the coldest bits which is the glass and then the fabric hood.

JayUK. The Z4 hood has a water proof membrane - no need to seal the fabric of the roof although many do - I would look for water ingress somewhere else - the drains off the back of the hood will fill the body cavities behind the doors. Not only will this drown your roof motor it vents (warm damp air on a sunny day or with the heating on full) into the cabin. You can see the gaps with the roof down and any build up of water. I would check the drains are clear and you've no standing water. Also look in the boot in the battery well and feel round the rear light clusters this seems to be another common leaking point.
Thanks for your response. However the car has been parked for a few days. I check the carpets and boot regularly and they are as dry as a bone. Have checked again this morning and still the same. I slipped my hand behind the roof lining to feel for any dampness and towards the front of the roof my hand came out a bit wet. It's not saturated but moist shall we say. Maybe I will get a couple of those De-Humidifying bags that "bmwforachange" recommended. Do not really want to seal the roof with the likes of Fabseal as I have read the comments on the forum regarding the Butyl membrane etc. :?

The boot and hood drains were more an item for JayUK to look at. I still stand by my comments about hot damp air condensing. If you've got the cabin hot without the AC being on then this is followed by a freezing cold night that might be enough to trigger a line of condensation - if you had screen blowers on the top of the screen is going to be where that hot damp air is as you lock it and walk away. Just what I'd start to think about first - as you say if carpets are dry and boot and drains are as well there's not many places left to look for moisture. Have you done any work on the doors and opened the membrane to get at the mechanism?
 
Crazy Harry said:
blunderthumbs said:
Crazy Harry said:
OP; given that you get condensation from hot damp air cooling (the top of the windscreen being further away from the blowers and therefore the coolest bit) ask your self why have you got hot damp air.

OK its very humid at the moment ... rain isn't the worst form of humidity very often the ground dries quickly after rain as the wind evaporates any water on the surface but at the moment the air has a lot of trapped water and the saturated ground or melting snow are a ready source for more. This time of year more than summer its important to run your air con to get hot dry cabin air - AC is not just for cool air in summer!

I know cars are vented but most seal well enough that if you park it dry it stays dry. Of course if its wet - damp carpets; seats etc if the sun gets on it the air warms - hot damp air rises and at night condenses onto the coldest bits which is the glass and then the fabric hood.

JayUK. The Z4 hood has a water proof membrane - no need to seal the fabric of the roof although many do - I would look for water ingress somewhere else - the drains off the back of the hood will fill the body cavities behind the doors. Not only will this drown your roof motor it vents (warm damp air on a sunny day or with the heating on full) into the cabin. You can see the gaps with the roof down and any build up of water. I would check the drains are clear and you've no standing water. Also look in the boot in the battery well and feel round the rear light clusters this seems to be another common leaking point.
Thanks for your response. However the car has been parked for a few days. I check the carpets and boot regularly and they are as dry as a bone. Have checked again this morning and still the same. I slipped my hand behind the roof lining to feel for any dampness and towards the front of the roof my hand came out a bit wet. It's not saturated but moist shall we say. Maybe I will get a couple of those De-Humidifying bags that "bmwforachange" recommended. Do not really want to seal the roof with the likes of Fabseal as I have read the comments on the forum regarding the Butyl membrane etc. :?

The boot and hood drains were more an item for JayUK to look at. I still stand by my comments about hot damp air condensing. If you've got the cabin hot without the AC being on then this is followed by a freezing cold night that might be enough to trigger a line of condensation - if you had screen blowers on the top of the screen is going to be where that hot damp air is as you lock it and walk away. Just what I'd start to think about first - as you say if carpets are dry and boot and drains are as well there's not many places left to look for moisture. Have you done any work on the doors and opened the membrane to get at the mechanism?
This is my first winter as owner of the car and it's not garaged unfortunately . I'm not aware of any work done to the doors but it's something I might check when the weather permits. I never switch the aircon off in any of my vehicles because as you say AC is not just for cool air in the summer. I'm not too concerned with a bit of condensation I was just curious to know what's causing it. There has been a good layer of snow (3") on the car till last week so that could have something to do with it. I only know about the drain holes behind the rear wings, are there any others I should pay attention to ? I'm one of the fortunate ones to have had the roof motor relocated to the boot. :thumbsup:
 
blunderthumbs. If anything's going to cool the top down its a good layer of snow - that on its own might have been enough with nice warm cabin air - or air entering the cabin as you get out after you've stopped.
 
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