W210 E320 CDi - Air con problem / misting up

[jovenden]

Hi folks, just got a used E320 CDi a few days ago - 46000 miles, lovely car *except*... driving around it just seems to mist-up on the side windows and the windscreen partially mists up (not so bad that you can't drive but if you look at t he windscreen instead of through it, you can see it.

Previous car was an E39 BMW and i never had any such problems - the aircon/climate control worked very efficiently.

The merc has air con and climate control panel and I have this set to auto - assume this will 'dehumidify' the interior - but seems I have to open the windows if I want to the misting to clear - not so good belting down the motorway with the family on board and a temp of -1 !

I have the vents open and have not been using the EC button and nor have I accidentally pressed the 'recirculate' button (a red light is illuminated when either of these switches is used).

Really appreciate any pointers as this is spoiling my enjoyment of what otherwise seems to be a superb car.

cheers
Jeremy

 

[AKM]

Hi if the red light on the EC button is iluminated on my E320 it means the air con is switched off. I think EC stands for economy mode, ie when its lit air con is off using less fuel.
Hope this helps.

 

[jovenden]

Thanks for the response, but I already knew that. The problem I am trying to describe is that with the aircon fully functional (well at least according to the variousl buttons and displays!), the car mists up...

many thanks
jeremy

 

[OlafMaxwell]

This could be bad news, the aircon is a known weak point to put it mildly. I believe the pollen filter could be a cause, but you might check if the system is cooling.

Mine gave a lot of trouble, died late last year, needed a condenser radiator, its behind the passenger side suspension strut under a cover, access from the top. Expensive, took them three attempts to sort out, system was regassed three times while they tried to source the problem. Get a good look at the problem, hope you have a warranty.

Meanwhile my 95 Peugeot has air con that never needed service.....

I agree the E320cdi is a superb car....but...but...but.

Another tip, have a look at your ABS/ESP pump housing near this and look out for the four pipes coming from the top of it, its an allow unit. Watch out for brake fluid leaks. There is another post on this site regarding sudden and total loss of braking on these cars. Merc say it can't happen but it does, I have experienced it twice [its fot to the floor and no brakes!!]and there is another post on this site with the same problem. Problem is the pump fails and it pumps all the fluid from both brake circuits out into fresh air leaving yuo with no brakes.

 

[jovenden]

Garage I used to use for my BMW (independent who do BMW and Mercedes servicing) suggested on the phone that is most likely to be:
1) blocked pollen fliters
2) blocked heater drains (I think that's what he said)

He reckons an hour tops to investigate/fix if it is either of these things - will be dropping the car in tomorrow and hope it is sorted because it is really unpleasant driving around with 3/4 of the windows covered in a layer of moisture!

No warranty - bought the car privately.

Bit worrying your comment about total brake failure!

cheers
Jeremy

 

[OlafMaxwell]

Jovenden I agree with,but in mine when we tested the system there was no cooling and you could hear the compessor trying to compress the non existent refrigerant which had leaked out through the condenser radiator.

Did you get any service records? Going on my reckoning you should have had at least two if not three services on the ASSYST.

 

[jovenden]

According to the garage, there is a flap which was not opening to allow the fresh air in - so it was effectively stuck in recirculation mode all the time! Car hasn't been used much in previous 12 months so hopefully it was just lack of use that caused it temporarily seize.... otherwise could become somewhat expensive..

 

[Hilton]

This is my first post, although I have read the forums with great interest (and sometimes depression !) as a recent MB owner (2000 W210 E320 CDI)

My W210 is displaying the same symptoms as Jovenden has described - misting windows, but mostly after the car has rested for about 1 or 2 hours following a long run (over 30 miles). Having cleaned the windows very carefully, the mist can be cleared by the heater fan within 20/30 seconds, but I am noticing heavy misting on the inside of the rear window in cold weather. Whe the fan starts up to clear the mist, I can detect a slightly acrid smell from the vents and if I were a betting man I would guess this smell is reminiscent of antifreeze !

I cannot detect that I am losing coolant volume, and the main MB dealer recently replaced the pollen filter (also physically checked). Vents and drain pipes appear clear. Am I facing a heater radiator replacement or should I check other things first ?

Grateful for any advice before shelling out lots of money ! Jovenden, has your problem been resolved ?

Regards

 

[jovenden]

I took mine to an independent Mercedes specialist for a check over - he found that the car wasn't drawing fresh air in - it seemed that something had seized (temporarily) so that even though I hadn't selected internal recirculation, this is what I was getting. I think the intake is under the bonnet, passenger side near the windscreen - check that this is definitely drawing air in.

My car hadn't been used much in the previous 12 months (around 1000 miles) but this now seems to be working correctly. It wasn't a repair - they guy just switched between recirc/non-recirc and it seemed to start working.

Hope this helps - it isnt necessarily something expensive....

 

[Hilton]

Jovenden, many thanks , I'll check out this first, but I am now looking for a good independent workshop in the Cambridge area - does anyone have a recommendation ?

I really hope its something simple as you suggest - is yours working fine now?

 

[jovenden]

All I can say is it *appears* to be working OK now.

let us know how it goes

 

[dishmop]

I find that a lot of window misting is caused by polish or some such crap which somebody has usd as a cleaner.

Just use water and scrub away until your arms ach with a piece of old terry towell. Do it when the glass is misted. You wipe it away and it comes back. You think it has gone but if you catch the light right, you can see the streaks and marks on the glass.

 

[Hilton]

Dishmop, thanks for the tip on cleanliness of windows - I have found the same and I reckon the misting has reduced as I have gradually cleaned them.

Yesterday I removed pollen filter and checked intake. Filter seems new (8/04) but I have run it today with the filter out to see if it made a difference. Alos used a can of COMMA aircon cleaner to purge the smells. Smells have gone and until a restart this evening, I experienced no misting at all. I'll see how it runs over the coming week, but I reckon I shall have to refit the filter eventually. My wife remembers an Allegro like my e-class (!), but was not such a problem with corrosion.