Mazda 6 Forums UK

Technical Section => Heating & Ventilation => Topic started by: Flying KD on November 22, 2012, 08:28:51 pm

Title: Windscreen Condensation
Post by: Flying KD on November 22, 2012, 08:28:51 pm
Hi

I have noticed recently in the colder damper weather that when the car has been lying overnight or through the day the windscreen has a large area of misting/condensation on the inside approximately where the dashboard vents blow. This takes a while to clear even with the A/C on and full airflow directed to the screen. I have had this on other cars but not as bad or taken as long to clear. The car has been back and the dealer says there are no external water leaks and the pollen filter is dry and has been cleaned.There certainly doesn't appear to be any water in the car, no damp carpets etc.
 Any body else experience this and is there a cure or is it a "feature"? I usually leave the car having switched the fan off prior to switching off and make sure that the airflow direction remains open, maybe I should switch to recirculate prior to switching off?
 Ideas and thoughts would be appreciated, otherwise the car is a great tool, quick and comfortable, nearly as good as my Subaru!
Title: Re: Windscreen Condensation
Post by: tubbs on November 23, 2012, 06:52:36 am
I had the same issue with my car. The dealer could not find any problem and blamed the pollen filter which was changed on the second service. I asked them to chase Mazda Uk as this is not acceptable for a nearly brand new car to have bad condensation on the inside. That was over six months ago and I am still waiting for a response from the dealer...... :-[ so not holding ones breath!!!!!

The issue also occurs on our other car which is also a M6. Let me know if you get a fix cheers

ps. Never had the problem with Honda's

Title: Re: Windscreen Condensation
Post by: Mazda6Driver on November 23, 2012, 07:55:35 am

My 6 seems pretty prone to 'steaming up' too.  Having said that, it's nowhere near as bad as the Leon I had previously.

I find it's worst on the back window, on a cold damp day like today, I need to demister on constantly to keep it clear.
Title: Re: Windscreen Condensation
Post by: jbconno on November 23, 2012, 08:27:42 am
Mine also does that.
Title: Re: Windscreen Condensation
Post by: DavidN on November 23, 2012, 02:32:14 pm
My last car - X type - was much worse, in this respect, than my M6. 
Title: Re: Windscreen Condensation
Post by: SM25T on November 26, 2012, 08:49:36 am
Pollen filter cleaned ? Does that mean they just removed it and tipped the big bits off ? This won't remove the fine particles that will clog the filter.

So easy to remove and replace. Don't even need to remove the glove box like I did on my previous 2006 car.

You can buy a filter on line very cheap.

You still have to clean the inside of the glass on front and rear screens on a regular basis. Proper glass cleaner. Never wipe the inside of the glass with your hand or a cloth when it is wet with condensation - you will make matters far worse !
Title: Re: Windscreen Condensation
Post by: Flying KD on November 28, 2012, 08:47:50 pm
I did wonder when they said the pollen filter had been cleaned but  because the car has only been on the road since April I let it go as they also said it was dry so it is not trapping water. I used to be a car valeter and always keep the glass clean. Non smokers and the vents always open so car doesn't get stale. I clean my class perfectly and free; I use warm water and a clean chamois to clean the glass  then screwed up dry newspaper to remove the dampness the chamois leaves. This removes all tar, grease and general dirt and works outside too, no wiper smearing! Think we have a problem with the rear screen, when it is switched on  now it causes radio interference, I sense earth or suppression problems and the rear window demister is very weak, still all under warranty, just time consuming.
Title: Re: Windscreen Condensation
Post by: jbconno on December 17, 2012, 09:26:46 pm
Its a common problem that you can hear the rear wiper through the radio. Like you said its possibly poor suppression ?
Title: Re: Windscreen Condensation
Post by: Bluzel2018 on May 21, 2017, 09:30:04 pm
Sorry to jump on an old post. But I had this same problem with radio interference with the rear window demister on my Lexus. It's because the radio aerial is build into the window at the top as part of the demister. When a slight hairline break of the demister/aerial wire appears it isnt a full connection then the aerial doesn't work 100%
Title: Re: Windscreen Condensation
Post by: mareng73 on June 05, 2019, 09:20:49 am
The filter in the heating/ ac system is not a pollen filter as its too flimsy.
I had a pollen filter in my last car (it wasn't a Mazda)   and it was far denser and a felt construction not flimsy paper( not unlike the anti-static sheets for tumble dryers) as that fitted in the Mazda, so it is just a filter to protect the fan & heat exchangers from leaves.

The condensation could be caused by running the system on Recirc. It is not really required to run the ac continuously, granted you need to run it occassionally to keep the seals lubricated but for the weather in the UK  there are few days that it is required.

If the ac has been run then it is  a good idea to turn off the compressor 5 minutes before you are going to stop but keep the fan running to dry out the evaporator and the plenum, so there is no condensation to cause this fogging particularly when the dew point falls overnight.
Condensation is caused by moist air hitting a cold surface.

On those that park under trees and don't garage the car, then water in the passenger footwell is caused by plenum drains being clogged with pollen and sap from trees.

The low side of the refrigerant system is on the suction side of the compressor after it has left the evaporator.
Title: Re: Windscreen Condensation
Post by: alan33 on February 12, 2024, 12:48:33 pm
My 2018 6 estate gets so misty on the inside of the windscreen that in winter I have to DEICE the inside as well as the outside of the windscreen, not  a lot of fun as the car has a HUD so have to either DEICE the inside before starting the car or mess around with the setup to stop the HUD standing up otherwise the water is going to drip inside the unit which I feel sure will not do it any good at all.
Alan