[Nadz]

I have a MY21 530 that I picked up in February. Since then on a few occasions, after the car has been parked (usually overnight / for a lengthy period of time) i get condensation on the inside of the windscreen. it is only around the middle section near where the main blowers are. I have never had this on any previous car and was wondering if anyone had a similar issue or could shed light on it?

Could it be a leak and moisture is just condensing or could it just be the air con?

Help appreciated

[Warp Ten]

Any chance you have your system set to recirculate air? That can sometimes create similar moisture in the car. From the manual, below, though it doesn't show the button symbol with the circular arrow inside a car. --Bob

Recirculated-air mode
Concept
You may react to unpleasant odors or pollutants
in the immediate environment by temporarily
suspending the supply of outside air. The system
then recirculates the air flow within the vehicle.
Operation
Press button repeatedly to select an operating
mode:
▷ LED off: outside air flows in continuously.
▷ LED on: the supply of outside air is permanently
shut off.
To prevent window fogging, recirculated-air
mode switches off automatically after a certain
amount of time, depending on the environmental
conditions.
With constant recirculated-air mode, the air quality
in the car's interior deteriorates and the fogging
of the windows increases.
If there is window condensation, switch off recirculated-
air mode

[Nadz]

Led is off so drawing outside air. Initially I thought it was just the air con not having fully dried the air out (e.g. if I had been sitting in the car with engine off for about 5 mins before exiting the car).

[dscabra]

This explanation should explain it:

"The movement of particles can explain this increase in condensation rate. When the hot air comes in contact with the cold glass, heat is transferred from the hot air to the cold glass. The loss of heat in the surrounding air causes the water vapor by the glass to lose energy. Once energy is lost, the water vapor condenses into liquid on the glass."

The glass is cooled by outside temps, which are not equal to inside temps. There may be some residual warm air in the ventilation system that is interacting with the cooler glass. If the center vents are closer to the heat source than the outer vents, it would allow the air to cool slightly as it moves away from the heat source, which would account for the lack of condensation on the outer edges of the glass.

[CnSky]

Think it's just thermal transfer.

Hot air holds more moisture, as it hits the very cold glass it drops the moisture due to thermal transfer as it cools. It's a more extreme version as happens if you breathe on a window your breath cools and drops moisture onto the surface.

How cold is it outside? is it only happening in the mornings/first start of the day? Do you live in a super humid country; example this happens all the time in places like Bangkok due to the sheer quantity of moisture in the air.

If it's happening on subsequent starts a few hours apart or on warm dry days maybe you should be more concerned and ask your dealer to have a look at your cabin filters etc.

This can happen in any car it's all down to temp and humidity, if you want to eliminate it buy one of those dehumidifier bags and stick it under your seat.

They can be restored by a few minutes in a microwave every month.

https://www.halfords.ie/motoring/car...er-170096.html

[Nadz]

Thanks CnSky dscabra - good explanation of the science behind it. I understand all of this but I have not had this issue on any of my previous cars and still live in the same location with similar weather patterns.

I am in Scotland so although it rains (a lot)and the temperature can be quite low. However, there is no pattern to it at all. I can leave it overnight (temps 0-5 Celsius) and nothing is there in the morning. However, yesterday the temp was about 10 and I had driven the car for 20 mins and parked up for 40 mins. When I came back to it the condensation was there.

I think that there has to be something in the air con not working right. there is no way with just me in the car, for a 20 minute drive can generate that level of warm air (I can certainly produce hot air though says the Mrs).

If I had the same issue on previous cars I could understand that it is the environment and my driving style. But I have not and my Wife's Mazda is driven the same amoun tof time and parked in a similar space, yet has no issues.

I have it booked in with the dealer next week so will see if they can diagnose anything.

[CnSky]

Could be two things ...

a bad filter or system problem or the heater in the BMW may be too good and immediately heats air.

Maybe test both your car and the Mazda and see how long it takes for hot air to start being pushed out.

I bet the BMW is immediate as I think it used a electrical heater and doesn't rely on the car engine heat.

FYI I'm in ireland and no condensation issue since December when I purchased the car but I never turn on max windscreen heat as I use precondition heat from the app/key to get the climate to my liking and ice off the windscreen before going out to the car.

[LogicalApex]

I'll preface my statement with I have a 530e so I don't know if BMW did anything differently on this front in the e over the ICE variants...

I precondition almost all the time, but couldn't this morning since I street park and my spot with my charger wasn't available when I got home last night. When I left this morning with a flat HV battery I noticed similar condensation. The car took a few minutes to activate CC and once CC was on it cleared the condensation instantly that had formed in the meantime.

I have noticed if I start out with a flat HV battery the car may take a minute or so to activate CC functions...

The manual does mention this for me as a downside noting that with a flat HV battery AC may not be immediately available (hence my earlier comment)...

Are you noticing the condensation after CC has started working? Or is this period with no CC a thing for your car as well?

[Nadz]

Thanks for the replies guys. Apologies if my original post was not clear. The condensation is there before I even start the car - so it is not created by warm air immediately coming out of the blowers. I have seen this on other cars where there is still warm air in the system / they heat up fast so within the first 30 seconds of the CC going on, the window mists and then subsequently clears. this is not the issue I am facing. My condensation builds up when the car is off and left for a period of time - the condensation is there before I even start the engine or CC.

When I start the car the air con is always on (I set to auto, AC on). it takes about a mile or so for the air to get warm and depending on how bad the condensation is, can take minutes for it to clear.

Mine is not the PHEV so I am not sure if the preconditioning is different. I thought in the other cars all the app does is turn the fan on (i.e. no heat) but I may be wrong. either way - I do not use the pre-conditioning.

[dscabra]

I found this in another forum:

Check the A/C drains are not blocked. The A/C condensates moisture from the air at the evaporator behind the dashboard. If the drains are blocked you will have a pool of water there ready to evaporate. The moisture will go up through the vents and condensate on the front windscreen.

You will need to look under the car approximately under the dashboard. There may be one or two open rubber pipes or holes as @Al_ says in the comments. You may need to poke something in the pipes to clean them out. Preferably use something plastic like a grass trimmer cord.

This video may help identify the location of the A/C drains.

[LogicalApex]

Originally Posted by Nadz

Thanks for the replies guys. Apologies if my original post was not clear. The condensation is there before I even start the car - so it is not created by warm air immediately coming out of the blowers. I have seen this on other cars where there is still warm air in the system / they heat up fast so within the first 30 seconds of the CC going on, the window mists and then subsequently clears. this is not the issue I am facing. My condensation builds up when the car is off and left for a period of time - the condensation is there before I even start the engine or CC.

When I start the car the air con is always on (I set to auto, AC on). it takes about a mile or so for the air to get warm and depending on how bad the condensation is, can take minutes for it to clear.

Mine is not the PHEV so I am not sure if the preconditioning is different. I thought in the other cars all the app does is turn the fan on (i.e. no heat) but I may be wrong. either way - I do not use the pre-conditioning.

The condensation is present before you enter the car? Meaning it was developing while the car was sitting idle and parked and you see it walking up to your car? If so, I haven't seen this and would definitely ask the dealer to check the car for a bad air seal as I haven't seen this in mine.

If the condensation isn't present before you get into the car then you're likely seeing what I saw this morning. The condensation this morning came from my body heat and breathing adding much warmer air into the cooler car and causing build up. It stuck around a bit due to the car not yet running AC to remove the condensation. It sounds like on your car it takes a minute or two for that to kick in just like the PHEV. If so, I'd say it is probably normal (or we both have cars with an issue).

You're right about preconditioning on the PHEV. Since it allows turning on the AC condenser and/or heater you can have this process started beforehand. It also allows you to get into the car and have instant heat or air. If memory serves me you'll get instant climate control in the PHEV if the HV battery has more than 5% charge on it when you start out or you precondition beforehand.

[Nadz]

Thanks again guys. I have it booked in next week so will keep you posted. I will let them poke about under the car. I do hope it's not a blocked pipe as that is bad for a 2 month old car.

The condensation is there before I get in and before car starts. I suspect it is something to do with the condenser or dryer. I had a problem with those components in my F10.

The MHT in the 530d bugs me. I don't see why the 48v battery can't run the heater for a few mins so I can precondition like a PHEV. Appreciate there will be more battery draw and the battery is smaller than the PHEV but even allowing 5 mins of 48v powered heating would help in cold mornings.

If only we had remote start in the Uk!

[dscabra]

Originally Posted by Nadz

Thanks again guys. I have it booked in next week so will keep you posted. I will let them poke about under the car. I do hope it's not a blocked pipe as that is bad for a 2 month old car.

The condensation is there before I get in and before car starts. I suspect it is something to do with the condenser or dryer. I had a problem with those components in my F10.

The MHT in the 530d bugs me. I don't see why the 48v battery can't run the heater for a few mins so I can precondition like a PHEV. Appreciate there will be more battery draw and the battery is smaller than the PHEV but even allowing 5 mins of 48v powered heating would help in cold mornings.

If only we had remote start in the Uk!

My solution -- heated garage!

[Cabbage]

I had this issue for the first time but it went away after a few seconds. I had air circulating on. Good that you found a solution that fits you though!

[LogicalApex]

Originally Posted by Nadz

Thanks again guys. I have it booked in next week so will keep you posted. I will let them poke about under the car. I do hope it's not a blocked pipe as that is bad for a 2 month old car.

The condensation is there before I get in and before car starts. I suspect it is something to do with the condenser or dryer. I had a problem with those components in my F10.

The MHT in the 530d bugs me. I don't see why the 48v battery can't run the heater for a few mins so I can precondition like a PHEV. Appreciate there will be more battery draw and the battery is smaller than the PHEV but even allowing 5 mins of 48v powered heating would help in cold mornings.

If only we had remote start in the Uk!

I guess they "solved" this with Remote Start on the LCI. But in true BMW fashion they didn't even make that consistent because well why make things consistent? lol... The LCI cars can start the engine to allow proper preconditioning using the heater or AC on the ICE cars, but the PHEV can still only do so with the HV battery and it can't wake the engine if the battery is flat. It also can't use the key to initiate precondioning like the ICE car can... But I don't have the LCI so I guess I shouldn't complain

In regards to why it isn't done in the pre-LCI cars with MHT without remote start this is due to the power draw. The heater is extremely power intensive. On my PHEV I get about 3700W out of the wall as I'm on Level 2 @ 16A 240V and when it is cold out I notice the car draws all of that and still needs to draw power from the battery as well. Which means it is probably using 5000W or so to run the heater. That would be far more than you'd have on hand with the small MHT battery so it wouldn't work.

[WMER]

Originally Posted by Nadz

Thanks again guys. I have it booked in next week so will keep you posted. I will let them poke about under the car. I do hope it's not a blocked pipe as that is bad for a 2 month old car.

The condensation is there before I get in and before car starts. I suspect it is something to do with the condenser or dryer. I had a problem with those components in my F10.

The MHT in the 530d bugs me. I don't see why the 48v battery can't run the heater for a few mins so I can precondition like a PHEV. Appreciate there will be more battery draw and the battery is smaller than the PHEV but even allowing 5 mins of 48v powered heating would help in cold mornings.

If only we had remote start in the Uk!

Hi Nadz, I have the same problem on my 520i, has there then been a solution from the dealer ?
Regards

[Nadz]

Originally Posted by WMER

Hi Nadz, I have the same problem on my 520i, has there then been a solution from the dealer ?
Regards

They had the car in for the day and apparently checked all seals and headlining for leaks. Didn't find any so I was told "it's normal. Moisture in system etc etc "

Thankfully not happened since.