Car suddenly misting up!

[Ari]

About two hours in to a long drive the other morning, air con off, and suddenly all the windows misted over on the inside!

Hit the demisting button on the climate control which boosts the fan right up, deflects the air to the screen, and turns on the air con, and it demisted in about a minute and was then fine for the rest of the journey. Never done it since.

Bit random though, anyone experienced similar or know why it happened?

[TonyRPH]

Damp carpets, leaking heater matrix perhaps?

[Herbs]

Another for damp carpets or had you hit the recirculate button by mistake as that can mist it up pretty quickly?

[V8LM]

Ari said:

About two hours in to a long drive the other morning, air con off, and suddenly all the windows misted over on the inside!

Urinary incontinence. Keep the A/C on.

[GTIR]

I'd magine you hit a cold area.
Warm inside cold outside = misty windows.

Stop breathing might help.

[C.A.R.]

Winding the window down a tiny bit will quickly clear mist from the inside of the car.

Can't believe this is the first experience of having windows suddenly mist up though!

[Deva Link]

Ari said:

Bit random though, anyone experienced similar or know why it happened?

Is this in your Merc?

I'm guessing a bit here, but when you turn the a/c off in a Merc (and many other cars too) it doesn't go fully off, it drops to maybe 30% of its capability, and then goes fully off after about 20mins. I got into a habit of turning the a/c off if I didn't need it due to it drying out my contact lenses.
It's really noticeable in my car (2005 C270CDi) and I can demist it by turning turning the a/c on and then off again - once the car starts to demist it'll continue to, even with the a/c apparently off.

However your 2 hour time period is a bit odd. Perhaps, like many other things, MB have messed around with the setting and in your car it doesn't go fully off for 2 hours? The percentages and time can be changed in StarDiagnose.

[Ren Esis]

Also check your pollen filter is not damp. This alone caused me nearly a month of frustration trying other remedies before I checked the filter.

[Ari]

TonyRPH said:

Damp carpets, leaking heater matrix perhaps?

Unlikely to suddenly happen after 2 hours, and then go away completely again...

[Ari]

V8LM said:

Urinary incontinence. Keep the A/C on.

More likely...

[Ari]

C.A.R. said:

Winding the window down a tiny bit will quickly clear mist from the inside of the car.

Can't believe this is the first experience of having windows suddenly mist up though!

I'll try that next time.

[jimxms]

Sometimes when I'm concentrating heavily on navigating a certain road (twisty in dark for example), my noggin gets really hot and steams up the windows. Weird?

[Ari]

Deva Link said:

Is this in your Merc?

I'm guessing a bit here, but when you turn the a/c off in a Merc (and many other cars too) it doesn't go fully off, it drops to maybe 30% of its capability, and then goes fully off after about 20mins. I got into a habit of turning the a/c off if I didn't need it due to it drying out my contact lenses.
It's really noticeable in my car (2005 C270CDi) and I can demist it by turning turning the a/c on and then off again - once the car starts to demist it'll continue to, even with the a/c apparently off.

However your 2 hour time period is a bit odd. Perhaps, like many other things, MB have messed around with the setting and in your car it doesn't go fully off for 2 hours? The percentages and time can be changed in StarDiagnose.

Interesting, thanks! And yes, is in the Merc.

[Ari]

jimxms said:

Sometimes when I'm concentrating heavily on navigating a certain road (twisty in dark for example), my noggin gets really hot and steams up the windows. Weird?

Yes, weird!