Front windscreen more misted up than other windows when cold

Sybaris · January 17, 2023

Is anyone else having this problem.

When the temperature is low and I come home to my car from a long day at the office, I find that the windscreen is misted up but not the other windows.

Is this normal or does this suggest an issue?

Thanks

Illogan · January 18, 2023

Just a thought Dan.

My windscreen does the same, (and then I realised that I parked the car facing the (normal) prevailing weather.

When I reverse the car into it's normal spot - - I don't have that problem!

NemesisUK · January 18, 2023

The windscreen is at a sharper angle compared to the other windows. Plus there are vents at its base

08ISF · January 18, 2023

Mine does the same and it's driving me mad, because the angle and size of the screen makes it so awkward to wipe it off. I've tried squeegeeing it and that drops water all over the dash. Worse still, these cold mornings and evenings the moisture is freezing on the inside of the glass. Fortunately Lexus' demisting facilities are pretty good so I don't have to wait too long for it to clear.

Las Palmas · January 18, 2023

If it de-mists as soon as you start the car, is it then an issue?

Sundance · January 18, 2023

This is a new one on me too, having only had the car a month. It's not just a mist on the inside of the windscreen it's significant condensation. Someone suggested it might be to do with the aircon in need of re-gassing but while I can see the air-flow connection I'm not sure why would it cause condensation 🤔.

royoftherovers · January 18, 2023

Sign of a blocked cabin air filter by glovebox ?

Sundance · January 18, 2023

19 minutes ago, royoftherovers said:

Sign of a blocked cabin air filter by glovebox ?

Good shout ... but mine is down as having been changed 6 months/2k miles ago.

NemesisUK · January 18, 2023

I've noticed the same in my RX but only on the first morning of a cold snap. Really heavy condensation on the windscreen and the panoramic roof. Subsequent mornings, nothing to note really, just a gentle fogging that disappears very quickly.

I wonder if it's down to the relatively large cabin volume? All cars will have a level of humidity in the cabin air and when the temp drops dramatically it has to condense somewhere (thankfully just on the windows!)?

Sybaris · January 18, 2023

It does demist but I wasn't sure if there was an issue

Bluemarlin · January 18, 2023

4 hours ago, Sundance said:

This is a new one on me too, having only had the car a month. It's not just a mist on the inside of the windscreen it's significant condensation. Someone suggested it might be to do with the aircon in need of re-gassing but while I can see the air-flow connection I'm not sure why would it cause condensation 🤔.

The climate control helps in reducing humidity while you're in the car by collecting condensation the air and draining it outside. Not saying the a/c is your problem, just how it can affect things.

In any event, here's an article on condensation:

https://mag.lexus.co.uk/fix-condensation-inside-car/

Vicmeldrew · January 18, 2023

I also have all the previously mentioned problems of condensation, freezing moisture and dripping on dash.

Anyone found the best settings for climate controls, switches to give best results of clearing and drying screen that actually work?

Bluemarlin · January 18, 2023

1 minute ago, Vicmeldrew said:

I also have all the previously mentioned problems of condensation, freezing moisture and dripping on dash.

Anyone found the best settings for climate controls, switches to give best results of clearing and drying screen that actually work?

Technically it's best to have the climate control on and set to outside air in colder months, as that way it removes the moist air from inside and replaces it with fresh.

Personally I leave mine permanently on auto, and I had no interior condensation yesterday, when it was very cold and the exterior windows were completely frosted over. Defrost cleared them in a little under 5 minutes.

NemesisUK · January 18, 2023

Just to be clear (see what I did there?) the a/c will not be functioning at temperatures below approx 5c to prevent the condenser from freezing. If the climate control is set to Auto everything it will switch to outside air, erm, automatically.

I will switch on the front screen demist as I switch on the rear screen and external mirrors defogger, leaving the climate set to Auto. That way the front screen demists quickly as the engine warms up. Pulling the sun visors down will help by trapping the air to the screen. I'm ready to drive away by the time I've scrapped the frost from the outside of the windows. I then switch off the rear screen defogger and turn on the heated steering wheel to warm my hands! The Climate Concierge has already switched on the heated seat 👍

royoftherovers · January 18, 2023

7 hours ago, Sundance said:

Good shout ... but mine is d?own as having been changed 6 months/2k miles ago.

might be a good idea to check ?

Vicmeldrew · January 18, 2023

Thanks Nemesis and Bluemarlin for your methods. I will give it a try tomorrow and see how it performs in my car.

Goodplan53 · January 19, 2023

This week I’ve also noticed significant condensation on the inside of the windscreen in both my RX and UX. I just put it down to the very cold weather. RX had its 6 year major service last week too (ouch!) - not sure if they’d replaced the cabin air filter.

Useful tip about air con not working below 5 degrees - didn’t know that, thank you Nemesis.

DavidCM · January 19, 2023

It's simply condensation exacerbated by freezing temperatures.

Sundance · January 19, 2023

42 minutes ago, DavidCM said:

It's simply condensation exacerbated by freezing temperatures.

I hope you're right David but I can't help but think there's more to it than that.

In all the years with all my cars and all the winter freezes I don't recall experiencing such moisture literally dripping onto the top of the dash. Besides which in this day and age, with modern cars and technology, it shouldn't be happening.

Investigations continue.

Phil xxkr · January 20, 2023

10 hours ago, Sundance said:

I hope you're right David but I can't help but think there's more to it than that.

In all the years with all my cars and all the winter freezes I don't recall experiencing such moisture literally dripping onto the top of the dash. Besides which in this day and age, with modern cars and technology, it shouldn't be happening.

Investigations continue.

I have experienced same and couldn't agree with you more, misting yes condensation never! And Oddly enough don't recall the same last year🤔

Bluemarlin · January 20, 2023

14 hours ago, Sundance said:

I hope you're right David but I can't help but think there's more to it than that.

In all the years with all my cars and all the winter freezes I don't recall experiencing such moisture literally dripping onto the top of the dash. Besides which in this day and age, with modern cars and technology, it shouldn't be happening.

Investigations continue.

I would think that there is more to it than that if it's actually dripping onto the dash. With this thread in mind I made a point of checking mine over the last few days, while it's been cold and frosty, and have had no condensation inside.

You might want to check your cabin filter just in case, it's only a 2 minute job. Also worth lifting all the mats to see if the carpets are damp, as well as checking all the boot storage areas, as there must be moisture somewhere in the car if there's that much condensation.

A light coating is understandable, but it shouldn't be to the extent that it's dripping.

Vicmeldrew · January 20, 2023

It’s been -2 for the last couple of mornings. Car has been well frosted outside but small amount of condensation inside. Set climate controls to Auto then pressed windscreen defrost button, it then turns Auto off and blasts air to screen. Cleared window pretty quickly with no dripping condensation. Pressed windscreen button off and system resumed in Auto with a/c selected. This method worked well for me.

I has a RX400h a few years ago which leaked loads of water. I did cure leaks but they came back again about 3 years later. I sold it and said I’d never buy another Lexus. However after a couple of other vehicles I did buy a RX450h against my better judgement. I don’t have any water ingress at present but if they appear in the future I will sell car and never buy another Lexus, ever. It’s ludicrous in this day and age that manufacturers can’t produce a durable watertight car.

First_Lexus · January 21, 2023

What I’m about to write is in no way scientific, but it is based on personal experience…

I get this on my windscreen in very cold weather only, when the car has been left unused for a couple of days with frost on the windscreen. I always use the climate control, can’t remember ever turning it off in any recent vehicle.

The thing is, I got the same effect with both of my NX, and previous Honda CR-Vs. It doesn’t happen often, perhaps three or four times each year depending on weather.

Sundance · January 21, 2023

22 hours ago, Bluemarlin said:

I would think that there is more to it than that if it's actually dripping onto the dash. With this thread in mind I made a point of checking mine over the last few days, while it's been cold and frosty, and have had no condensation inside.

You might want to check your cabin filter just in case, it's only a 2 minute job. Also worth lifting all the mats to see if the carpets are damp, as well as checking all the boot storage areas, as there must be moisture somewhere in the car if there's that much condensation.

A light coating is understandable, but it shouldn't be to the extent that it's dripping.

Mine has a relatively new cabin filter (just 2k miles ago/Jul '22) and I've checked and it is clean. Have also lifted and felt under the mats and nothing appears untoward, including the boot space(s).

It's a bit of a puzzle but as a precaution I bought a car de-humidifer (basically a bag of rice!) and sat it on the top of the dash last night. After another night of -2deg the inside of the windscreen was clear of both mist and condensation! 👍

Maybe not a long-term answer but certainly drip-preventing. Investigations continue.

Sundance · January 21, 2023

17 hours ago, Vicmeldrew said:

It’s been -2 for the last couple of mornings. Car has been well frosted outside but small amount of condensation inside. Set climate controls to Auto then pressed windscreen defrost button, it then turns Auto off and blasts air to screen. Cleared window pretty quickly with no dripping condensation. Pressed windscreen button off and system resumed in Auto with a/c selected. This method worked well for me.

I has a RX400h a few years ago which leaked loads of water. I did cure leaks but they came back again about 3 years later. I sold it and said I’d never buy another Lexus. However after a couple of other vehicles I did buy a RX450h against my better judgement. I don’t have any water ingress at present but if they appear in the future I will sell car and never buy another Lexus, ever. It’s ludicrous in this day and age that manufacturers can’t produce a durable watertight car.

Your 400h didn't have a sun roof by any chance did it? Known leakage issues, so I'm told, which is why I made sure my recent purchase doesn't have one!