Condensation and coolant
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1987 C126 500 SEC 1989 C126 560 SEC 2013 S212 E220
Condensation and coolant
Hi guys needed some advise on why I have a huge amount of condensation on my front windscreen.
I've got a S212 E220d with 168k miles on the clock. I bought it in August 2017 and all was fine in the summer. As the colder winter weather came in I started to notice condensation on the windscreen.
I thought nothing of it at first but as the temperatures got colder the condensation got worse. It's gone to the point that it freezes on the inside of the windscreen. And when defrosted has to be mopped up with a towel as it starts to drop inside the dashboard down the windscreen.
So i checked to see if I was losing coolant to see if I had a leaking heater matrix and the expansion tank seems fine. Also I've checked round the footwells and all is dry.
I do get heat but I feel it doesn't get hot very quickly but not sure if that has anything to do with my problem. Is there anything I'm missing? Should I check anything else?
Also when checking the coolant reservoir the fluid was brown and looked filthy. I've read somewhere that you don't need to change the coolant for 15years or 150k miles whichever comes first. Is mine supposed to be brown as someone else mentioned theirs was brown Too?
I'm going to be attempting a coolant change myself in the next couple of days, there's threads on how to do it on the net so will follow that with MB approved coolant and inhibitor. Should I change my thermostat in Case the brown coolant is clogging it up?
Just need to know why I have so much condensation and if anyone else is suffering from it too.
any help or advice would be greatly appreciated.
I've got a S212 E220d with 168k miles on the clock. I bought it in August 2017 and all was fine in the summer. As the colder winter weather came in I started to notice condensation on the windscreen.
I thought nothing of it at first but as the temperatures got colder the condensation got worse. It's gone to the point that it freezes on the inside of the windscreen. And when defrosted has to be mopped up with a towel as it starts to drop inside the dashboard down the windscreen.
So i checked to see if I was losing coolant to see if I had a leaking heater matrix and the expansion tank seems fine. Also I've checked round the footwells and all is dry.
I do get heat but I feel it doesn't get hot very quickly but not sure if that has anything to do with my problem. Is there anything I'm missing? Should I check anything else?
Also when checking the coolant reservoir the fluid was brown and looked filthy. I've read somewhere that you don't need to change the coolant for 15years or 150k miles whichever comes first. Is mine supposed to be brown as someone else mentioned theirs was brown Too?
I'm going to be attempting a coolant change myself in the next couple of days, there's threads on how to do it on the net so will follow that with MB approved coolant and inhibitor. Should I change my thermostat in Case the brown coolant is clogging it up?
Just need to know why I have so much condensation and if anyone else is suffering from it too.
any help or advice would be greatly appreciated.
MBWorld Fanatic!
Joined: Oct 2010
Posts: 5,141
Likes: 1,293
From: Southern US
2010 E550, 273 Engine: 2012 S550, 278 Engine
Hi guys needed some advise on why I have a huge amount of condensation on my front windscreen.
I've got a S212 E220d with 168k miles on the clock. I bought it in August 2017 and all was fine in the summer. As the colder winter weather came in I started to notice condensation on the windscreen.
I thought nothing of it at first but as the temperatures got colder the condensation got worse. It's gone to the point that it freezes on the inside of the windscreen. And when defrosted has to be mopped up with a towel as it starts to drop inside the dashboard down the windscreen.
So i checked to see if I was losing coolant to see if I had a leaking heater matrix and the expansion tank seems fine. Also I've checked round the footwells and all is dry.
I do get heat but I feel it doesn't get hot very quickly but not sure if that has anything to do with my problem. Is there anything I'm missing? Should I check anything else?
Also when checking the coolant reservoir the fluid was brown and looked filthy. I've read somewhere that you don't need to change the coolant for 15years or 150k miles whichever comes first. Is mine supposed to be brown as someone else mentioned theirs was brown Too?
I'm going to be attempting a coolant change myself in the next couple of days, there's threads on how to do it on the net so will follow that with MB approved coolant and inhibitor. Should I change my thermostat in Case the brown coolant is clogging it up?
Just need to know why I have so much condensation and if anyone else is suffering from it too.
any help or advice would be greatly appreciated.
I've got a S212 E220d with 168k miles on the clock. I bought it in August 2017 and all was fine in the summer. As the colder winter weather came in I started to notice condensation on the windscreen.
I thought nothing of it at first but as the temperatures got colder the condensation got worse. It's gone to the point that it freezes on the inside of the windscreen. And when defrosted has to be mopped up with a towel as it starts to drop inside the dashboard down the windscreen.
So i checked to see if I was losing coolant to see if I had a leaking heater matrix and the expansion tank seems fine. Also I've checked round the footwells and all is dry.
I do get heat but I feel it doesn't get hot very quickly but not sure if that has anything to do with my problem. Is there anything I'm missing? Should I check anything else?
Also when checking the coolant reservoir the fluid was brown and looked filthy. I've read somewhere that you don't need to change the coolant for 15years or 150k miles whichever comes first. Is mine supposed to be brown as someone else mentioned theirs was brown Too?
I'm going to be attempting a coolant change myself in the next couple of days, there's threads on how to do it on the net so will follow that with MB approved coolant and inhibitor. Should I change my thermostat in Case the brown coolant is clogging it up?
Just need to know why I have so much condensation and if anyone else is suffering from it too.
any help or advice would be greatly appreciated.
Is your heater on AUTO and the air flow direction on WINDSHIELD DEFROST? AUTO means that when you select WINDSHIELD DEFROST also the A/C comes ON to dry the air that is blown on the windshield so it does not bring more moisture to the cold windshield and should help keep the glass free of condensation. With AUTO defrost the air blows very hard so it has volume to keep windshield dry. After the windshield surface has warmed up the system does not need to be blowing that hard and the WINDSHIELD DEFROST can be canceled and just the mode of some air directed to the windshield can be used. AUTO should take care of this and direct some air to the windshield and some to the foot well.
Brown and filthy coolant is not a good sign unless someone put brown and filthy coolant in the engine, which of course is not the case. Coolant should have the color that it has as new like after 140 000+ miles in my car is still green. Brown and filthy coolant for me is a big alarm as it likely is a result of head gasket failure. With the car running open the reservoir cap (not the cap on radiator) and see if you have bubbles raising up in the surface. If you do you have a big problem.
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1987 C126 500 SEC 1989 C126 560 SEC 2013 S212 E220
Thanks for help Arrie, it's been a horrible rainy day today so haven't been able to change the coolant yet. However I did start the engine and remove the expansion tank cap but didn't notice any bubbles. Should I have let someone give it some gas or should I have let it run for longer as i only let it run for like 20/30secs. Looking at the coolant more closely today it didn't look dirty with any particles it's just a nasty brown colour. I've never seen that colour before.
I really do hope it's not a head gasket. I checked the underside of the oil filler cap as well and there's no milky residue, it's good clean oil. Also although there is smoke from the exhaust now and again I wouldn't class it as white smoke.
And yeah when I put the blower on defrost I use the the a.c. and use the switch that has the windscreen symbol on it blowing maximum air to the windscreen. Thing is, yeah it puts out a lot of air but because the condensation has frozen it melts and drips down the windscreen and who knows what kind of issues the water droplets will be creating there over time. I'm trying to work out why I have so much moisture in the car that it condenses so heavily and freezes on really cold mornings.
I've got a 1987 500 sec which doesn't suffer from condensation as badly as this does. And I'm aware that there's always moisture around us and we can bring moisture in via wet shoes and other stuff but I've never seen it this bad in all the cars I've owned.
I may have to pull some carpets up and see if there is any water collecting anywhere, possibly leaking in from somewhere.
I really do hope it's not a head gasket. I checked the underside of the oil filler cap as well and there's no milky residue, it's good clean oil. Also although there is smoke from the exhaust now and again I wouldn't class it as white smoke.
And yeah when I put the blower on defrost I use the the a.c. and use the switch that has the windscreen symbol on it blowing maximum air to the windscreen. Thing is, yeah it puts out a lot of air but because the condensation has frozen it melts and drips down the windscreen and who knows what kind of issues the water droplets will be creating there over time. I'm trying to work out why I have so much moisture in the car that it condenses so heavily and freezes on really cold mornings.
I've got a 1987 500 sec which doesn't suffer from condensation as badly as this does. And I'm aware that there's always moisture around us and we can bring moisture in via wet shoes and other stuff but I've never seen it this bad in all the cars I've owned.
I may have to pull some carpets up and see if there is any water collecting anywhere, possibly leaking in from somewhere.
MBWorld Fanatic!
Joined: Oct 2014
Posts: 1,053
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2011 E-350 4Matic Sport
I will preface by saying I change fluids more often than factory says I have to. I think oil, brake, diff, and coolant collect debris as well as lubricate/cool and its always been cheap insurance to me to change them on a regular basis. It also gives me the chance to inspect things and its a minor cost. But that's me expressing my perspective , others will equally argue they've been fine with factory intervals. But yeah I'm a fluid changer lol.
For the coolant, its collecting metallic and rubber debris over time and miles, plus the fluid itself breaks down over time. In your case I would suggest a complete flush and new fill. You may need to flush several times. I typically replace the thermostat at the same time - it has seen thousands of hot cold cycles and it can have debris buildup. I'm guessing yours should be changed based on your description of the coolant itself.
Kind of related but have you ever flushed the brake fluid?
For the coolant, its collecting metallic and rubber debris over time and miles, plus the fluid itself breaks down over time. In your case I would suggest a complete flush and new fill. You may need to flush several times. I typically replace the thermostat at the same time - it has seen thousands of hot cold cycles and it can have debris buildup. I'm guessing yours should be changed based on your description of the coolant itself.
Kind of related but have you ever flushed the brake fluid?
Senior Member
Joined: Apr 2016
Posts: 457
Likes: 151
From: Phoenix, AZ
2016 E350 Sport 2WD
My GUESS is that your evaporator/heater housing drain is plugged up to some degree, probably a lot. I've never looked at your model but speaking generally, there is a drain tube that allows all fluids to drain from the housing. When the drain tube is clogged, even partially, the draining doesn't work so well. When you turn on your heater, the air blows by the accumulated fluid, becomes moist, and it is blown up on the windshield. If there was no fluid in there, it wouldn't end up on the windshield. Do a search for how to clear the drain tube for your model. You Tube often has great videos of simple repair tasks.
MBWorld Fanatic!
Joined: Mar 2014
Posts: 3,107
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From: West Central Florida
2011 E550 P2 4M Sedan
Sounds like high humidity in the car and cold outside air is leading to the excessive moisture on inside of windshield. If AC is running to help dry the air and there is no excessive moisture present in car, then defrost mode should handle it for you. Don't drive with air recirculate on much - you want the drier outside air coming in. Also check the air intake cowl to be sure it is not blocked up.
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MBWorld Fanatic!
Joined: Oct 2010
Posts: 5,141
Likes: 1,293
From: Southern US
2010 E550, 273 Engine: 2012 S550, 278 Engine
Thanks for help Arrie, it's been a horrible rainy day today so haven't been able to change the coolant yet. However I did start the engine and remove the expansion tank cap but didn't notice any bubbles. Should I have let someone give it some gas or should I have let it run for longer as i only let it run for like 20/30secs. Looking at the coolant more closely today it didn't look dirty with any particles it's just a nasty brown colour. I've never seen that colour before.
I really do hope it's not a head gasket. I checked the underside of the oil filler cap as well and there's no milky residue, it's good clean oil. Also although there is smoke from the exhaust now and again I wouldn't class it as white smoke.
And yeah when I put the blower on defrost I use the the a.c. and use the switch that has the windscreen symbol on it blowing maximum air to the windscreen. Thing is, yeah it puts out a lot of air but because the condensation has frozen it melts and drips down the windscreen and who knows what kind of issues the water droplets will be creating there over time. I'm trying to work out why I have so much moisture in the car that it condenses so heavily and freezes on really cold mornings.
I've got a 1987 500 sec which doesn't suffer from condensation as badly as this does. And I'm aware that there's always moisture around us and we can bring moisture in via wet shoes and other stuff but I've never seen it this bad in all the cars I've owned.
I may have to pull some carpets up and see if there is any water collecting anywhere, possibly leaking in from somewhere.
I really do hope it's not a head gasket. I checked the underside of the oil filler cap as well and there's no milky residue, it's good clean oil. Also although there is smoke from the exhaust now and again I wouldn't class it as white smoke.
And yeah when I put the blower on defrost I use the the a.c. and use the switch that has the windscreen symbol on it blowing maximum air to the windscreen. Thing is, yeah it puts out a lot of air but because the condensation has frozen it melts and drips down the windscreen and who knows what kind of issues the water droplets will be creating there over time. I'm trying to work out why I have so much moisture in the car that it condenses so heavily and freezes on really cold mornings.
I've got a 1987 500 sec which doesn't suffer from condensation as badly as this does. And I'm aware that there's always moisture around us and we can bring moisture in via wet shoes and other stuff but I've never seen it this bad in all the cars I've owned.
I may have to pull some carpets up and see if there is any water collecting anywhere, possibly leaking in from somewhere.
The brown color of the coolant is not normal though the color probably darkens from the original with high mileage. I have seen brown coolant before in two cars that had the head gasket problem and they both had bubbles coming in the reservoir when the engine was hot and running.
To check for the head gasket is to do the cylinder compression test. That will tell.
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Thread Starter
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1987 C126 500 SEC 1989 C126 560 SEC 2013 S212 E220
Sorry for the late reply guys.
So my freezing windscreen problem was fixed after I had the windscreen replaced. It had loads of small chips in it so had it changed, it would seem that it must've been replaced at some point in the cars life but not sealed properly. Since its been changed I had no more condensation on the inside of the windscreen.
also I noticed that since the camera was recalibrated after the windscreen install the auto wipers actually work correctly. Before the wouldn't operate correctly when it was raining but now they're fine, I mean it's not the best but at least I don't have to do it manually anymore.
I still haven't addressed the coolant issue though, will attempt that this week. Also I'll book it in to do a compression test.
I'm not sure If I should start a new thread for my next issue but I'll ask it here anyway.
I have this funny burning plastic smell that comes from the engine compartment ( passenger side I think) , I can't seem to trace where from though. It doesnt always appear either so when I take it to the garage it's never present. One day it was bad, I parked up in the drive and just let the engine idle while I browsed my phone, I looked up after about 15 mins and there was smoke coming out of the engine compartment, I turned the engine off but could not trace the source nor has it ever happened again.
I've always thought it may be a plastic cover coming into contact with the hot engine now and again but nothing seems burnt or melting.
Anyone had this problem or heard of it? Many thanks.
So my freezing windscreen problem was fixed after I had the windscreen replaced. It had loads of small chips in it so had it changed, it would seem that it must've been replaced at some point in the cars life but not sealed properly. Since its been changed I had no more condensation on the inside of the windscreen.
also I noticed that since the camera was recalibrated after the windscreen install the auto wipers actually work correctly. Before the wouldn't operate correctly when it was raining but now they're fine, I mean it's not the best but at least I don't have to do it manually anymore.
I still haven't addressed the coolant issue though, will attempt that this week. Also I'll book it in to do a compression test.
I'm not sure If I should start a new thread for my next issue but I'll ask it here anyway.
I have this funny burning plastic smell that comes from the engine compartment ( passenger side I think) , I can't seem to trace where from though. It doesnt always appear either so when I take it to the garage it's never present. One day it was bad, I parked up in the drive and just let the engine idle while I browsed my phone, I looked up after about 15 mins and there was smoke coming out of the engine compartment, I turned the engine off but could not trace the source nor has it ever happened again.
I've always thought it may be a plastic cover coming into contact with the hot engine now and again but nothing seems burnt or melting.
Anyone had this problem or heard of it? Many thanks.
Thread Starter
Newbie
Joined: Jan 2018
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1987 C126 500 SEC 1989 C126 560 SEC 2013 S212 E220
Well I've come across 2 possible things it might be but then again it could be anything
this person had a minor leak from the cam cover
https://mbworld.org/forums/w211-amg/598292-bad-alternator-voltage-regulator.html
then this person says it's most likely the car going through a dpf regen which sounds more plausible
https://www.pistonheads.com/gassing/topic.asp?t=1419435
again it would be great if anyone here could point me in the right direction.
Thanks again.
this person had a minor leak from the cam cover
https://mbworld.org/forums/w211-amg/598292-bad-alternator-voltage-regulator.html
then this person says it's most likely the car going through a dpf regen which sounds more plausible
https://www.pistonheads.com/gassing/topic.asp?t=1419435
again it would be great if anyone here could point me in the right direction.
Thanks again.
