De-misting problem

Stew2508

New Member
Joined
Nov 13, 2017
Messages
5
Reaction score
0
Your Mercedes
C220 CDI Blueefficiency Sport / 2011 / 2.1ltr
Hi all. So just bought my first MB on Saturday, a beautiful 2011 C220 CDI Blueefficiency Sport. However I've got bit of problem with it. The left side of the windscreen mists up and doesn't clear. It's extremely weird as the right side is completely clear. I've tried about everything possible to clear it up such front windscreen demister, recirculation, hot and cold, a/c on and off, Windows down etc.... But nothing clears it. Has anyone else experienced this?

Thanks in advance.
 

Attachments

  • IMG-20171113-WA0001.jpg
    IMG-20171113-WA0001.jpg
    148.9 KB · Views: 29

Rotorhead500

Senior Member
Joined
Oct 19, 2012
Messages
5,815
Reaction score
2,650
Location
Very South Devon
Your Mercedes
Used to have a C63...
Welcome!

May be worth checking all drains in front of the windscreen are clear on that side (in the black scuttle panel). Is there any damp on the carpets in passenger footwell?
 

L John

Senior Member
Joined
Nov 24, 2013
Messages
2,860
Reaction score
553
Location
UK
Your Mercedes
W204 C350 Petrol Elegance
You either have poor/no airflow on the passenger side screen vent or you have moisture coming in at that side.
First thing is to check the airflow at the normal side and problem side. Use anything that wags in airflow to compare.

There are several electrically operated vent flaps behind the dash, my bet is one of the vent flaps is stuck in the closed position.
Unless it was a private sale, sold as seen, you should be taking it straight back to the seller to let them sort it out. There should be no problem as it's a dangerous vehicle if your screen is obscured with condensation and cannot self clear.
 
OP
S

Stew2508

New Member
Joined
Nov 13, 2017
Messages
5
Reaction score
0
Your Mercedes
C220 CDI Blueefficiency Sport / 2011 / 2.1ltr
  • Thread Starter
  • Thread starter
  • #5
Thanks I will check it out and get back to you and let you know what I find. I will also give the dealer a call and get them to have a look at it.
 
OP
S

Stew2508

New Member
Joined
Nov 13, 2017
Messages
5
Reaction score
0
Your Mercedes
C220 CDI Blueefficiency Sport / 2011 / 2.1ltr
  • Thread Starter
  • Thread starter
  • #6
So, I've checked the carpets around the passenger side and they are bone dry, I've checked the drain holes on the windscreen tray and those are clear. I took off the box by the passenger side blower under the bonnet and there is no side of water in their as it is bone dry. I haven't checked the pollen filter as I don't know where it is located. Anything else I can check before getting it back to the dealer on Saturday? Thanks
 
OP
S

Stew2508

New Member
Joined
Nov 13, 2017
Messages
5
Reaction score
0
Your Mercedes
C220 CDI Blueefficiency Sport / 2011 / 2.1ltr
  • Thread Starter
  • Thread starter
  • #7
Oh the air flow seems OK as well by the windscreen so I don't think the vents are stuck closed. Thanks
 

L John

Senior Member
Joined
Nov 24, 2013
Messages
2,860
Reaction score
553
Location
UK
Your Mercedes
W204 C350 Petrol Elegance
No water anywhere and good airflow on both sides?
I'd be interested to hear the outcome of this one.

In the meantime aircon will reduce the moisture content of the air to at least minimise the problem until its sorted. Don't use recirculate, you need fresh air coming in but if that was the issue you would have the problem on both sides.
 

LostKiwi

Senior Member
Joined
Aug 25, 2006
Messages
31,328
Reaction score
21,575
Location
Midlands / Charente-Maritime
Your Mercedes
'93 500SL-32, '01 W210 Estate E240 (RIP), 02 R230 SL500, 04 Smart Roadster Coupe, 11 R350CDi
Misting occurs when relatively warm moisture laden air hits a colder surface. Cold air can retain less moisture so the excess moisture condenses onto the cold surface. Using the demisters increases the temperature of the glass reducing the ability for misting to occur and using the aircon in conjunction reduces the moisture content of air flowing past the screen.
Therefore for misting to occur you either have excessive moisture on that side of the car (water somewhere in the air stream), ineffective heat on that side of the screen, ineffective aircon on that side of the screen or ineffective airflow.
 
Last edited:

malcolm E53 AMG

Senior Member
Joined
Aug 21, 2005
Messages
6,993
Reaction score
4,596
Check that the windscreen hasn’t been replaced recently they are notorious for this sort of problem if they aren’t 100% sealed
 

John Laidlaw

Senior Member
Joined
Nov 15, 2013
Messages
26,373
Reaction score
9,163
Location
Wirral
Your Mercedes
Land Rover Discovery 4
^ what he said ! Try cracking the front window open slightly whilst demisting until you get to the bottom of the problem...
 

oigle

Senior Member
Joined
Mar 15, 2005
Messages
3,467
Reaction score
914
Age
83
Location
Redcliffe, Queensland, Australia
Website
members.optusnet.com.au
Your Mercedes
2003 ML270 sold but not forgotten. 2022 Kia EV6 RWD LR
That would depend entirely on what the weather was like outside. If rainy, use recirc, if fine, use fresh. No point in allowing moisture laden air to enter the system.

No water anywhere and good airflow on both sides?
I'd be interested to hear the outcome of this one.

In the meantime aircon will reduce the moisture content of the air to at least minimise the problem until its sorted. Don't use recirculate, you need fresh air coming in but if that was the issue you would have the problem on both sides.
 

L John

Senior Member
Joined
Nov 24, 2013
Messages
2,860
Reaction score
553
Location
UK
Your Mercedes
W204 C350 Petrol Elegance
That would depend entirely on what the weather was like outside. If rainy, use recirc, if fine, use fresh. No point in allowing moisture laden air to enter the system.

No, never to use recirculate in an attempt to clear the screen whatever the weather, if it's already fogging up recirculate would be the worst thing to do.
 

umblecumbuz

Senior Member
Joined
Sep 20, 2010
Messages
4,431
Reaction score
1,875
Location
Wales and Gozo
Your Mercedes
S204 and CLC 204 cdi, MX5, Kia Soul
.... and the pollen filter will affect both sides of the screen equally.

This has to be a stuck ot inop directional flap somewhere, or residual water on that side of the system. Possibly leaving the system on full blast for an extended period might help clear any excessive moisture?
 

LostKiwi

Senior Member
Joined
Aug 25, 2006
Messages
31,328
Reaction score
21,575
Location
Midlands / Charente-Maritime
Your Mercedes
'93 500SL-32, '01 W210 Estate E240 (RIP), 02 R230 SL500, 04 Smart Roadster Coupe, 11 R350CDi
OP, do you get heat out of the left side demister vents?
 

LostKiwi

Senior Member
Joined
Aug 25, 2006
Messages
31,328
Reaction score
21,575
Location
Midlands / Charente-Maritime
Your Mercedes
'93 500SL-32, '01 W210 Estate E240 (RIP), 02 R230 SL500, 04 Smart Roadster Coupe, 11 R350CDi
Please explain reason for your statement....

The quickest way to do it is as follows:

  • Defroster fan on highest setting
  • Temperature control on its hottest
  • A/C turned on
  • Recirculate turned off
  • Crack your windows open 1/2 " or so
 

oigle

Senior Member
Joined
Mar 15, 2005
Messages
3,467
Reaction score
914
Age
83
Location
Redcliffe, Queensland, Australia
Website
members.optusnet.com.au
Your Mercedes
2003 ML270 sold but not forgotten. 2022 Kia EV6 RWD LR
Totally agree except for when it is raining outside as I said before. This video was on the premise of outside air being fresh and dry, if you listen. No value at all in bringing saturated air inside and then having to dry that too....
 

umblecumbuz

Senior Member
Joined
Sep 20, 2010
Messages
4,431
Reaction score
1,875
Location
Wales and Gozo
Your Mercedes
S204 and CLC 204 cdi, MX5, Kia Soul
Ahh ... but does aircon work as well when recirculating cabin air?
If so, it would continue to remove moisture from the air with all windows closed, resulting in desert-dry fug as opposed to jungle-humid fug.
 

Frontstep

Senior Member
Joined
Apr 22, 2007
Messages
9,201
Reaction score
3,436
Your Mercedes
T210 320cdi
Mt fug goes through carbon filters so its pretty clean and dry fug.
 

Stop looking for the Best Garage!! We are here and have the best advanced solutions for you, at Competitive prices. Put us to test with any issue you may have.
Top Bottom