Smell when AC is switched OFF

[HelpThisDude]

Hello All.
There are a few smelly AC posts on here, however this one seems different.
With the AC switched On, eveything is OK, no humidity or smells. Once I hit the EC button (AC OFF) the windows mist, the air is very humid, and it starts to smell.

Other then the obvious, leaving the AC on all the time, what could I do to fix this, and what could be the cause?

MB suggest a AC service, he said they check the drains are clear, change the combi filter under the glove box and run a fungus killer through. Just over £200.
Should i just pay up ?

*Someone suggested a leaking Heater matrix. But im not loosing coolant and I have only just last week re-fitted all the carpets, so I know it was not soaked down there.

Its a W203 C270CDi

 

[124coupe]

Do it yourself.....

Check the drains are clear (waggle some curtain wire in the rubber tubes where they pop out underneath (you didn't dislodge or block them when you did the carpets did you??)).

Change the combi filter (5 mins)

Run a £10 aerosol tin of (from Halfords) Comma "anti-stink" through the system (10 mins while you drink coffee). It de-odorises the carpets and seats at the same time so vac the car first..

Change from £35.....

(if the heater matrix was leaking you would smell the sickly smell of antifreeze....)

 

[HelpThisDude]

I didnt see any hoses when I moved the carpets. Well worth another look up there...
Silly questions.... Where would the hoses pop out of my car? trans tunnel? and how long a wire should I use and how far to shove it up there? Do they normally block up condenser side or ground level?

 

[HelpThisDude]

Just to confirm, is Item 70 the filter I need to change?
http://www.detali.ru/cat/oem_mb2.as...648716.649&CT=F&cat=69J&SID=83&SGR=045&SGN=01

 

[Hertfordshire Merx]

Replace the combination filter and the recirculation flap motor may need testing. You can do this by removing the combination filter which is just above the vehicle battery on th near side, easy to do by releasing three spring clips and you will see the recirc flap. Have someone sit in the car operating the recirculate button and you should see the flap open and close.

 

[LYNALL]

Item 430 is one of the drain tubes, mine come out either side of the gearbox so guessing yours similiar.



Lynall

 

[124coupe]

Yes the tubes come out underneath either side of the trans. Usually a "globby" lump in the end of the tube (either top or bottom) . When you had the carpets out you should have seen them snake down round the tunnel.

DON'T pull them out as they are a pig to put back.

From the dealer network, Inchape online ( http://www.mercedes-benz-parts.co.uk/ ) probably cheapest now as they have 10% off and a 10% rebate on filters etc tis month.

Order by VIN/reg on the website and be sure of the right part.

On my W124 I decided to use the pressure washer (carefully) and blew back both drains a few times, each time letting them empty back out...filthy water came out the first few times!

 

[HelpThisDude]

£74 for a combi filter! - however, MB told today that I have no Combi filter (the one by the blower motor under the glove box). Im confused now because the diagram above shows one.
I'll check over the weekend see if i have the two slots for the filters.
Hertfordshire Merx, cheers - I will pull the pollen filter and do the recirc flap test, cheers pal.
I didnt see any tubes snaking down the tunnel.

 

[HelpThisDude]

Just to add, the filter above the battery, I changed about 12-13k miles ago. It still looks new. I thought that was a pollen filter, and Items marked 70 were the combi filters?

 

[Hertfordshire Merx]

Just to confirm, is Item 70 the filter I need to change?
http://www.detali.ru/cat/oem_mb2.as...648716.649&CT=F&cat=69J&SID=83&SGR=045&SGN=01

To confirm, items 70 are acivated charcoal filters, not combination/pollen filters. These need replacing every 4 years unlike the combination filter which is replaced every B service.

 

[HelpThisDude]

Cool, thanks Hertfordshire Merx, I have no history of that filter ever being changed. But MB say My car does not have one. I had a look today, and I have no covers to remove by the blower, so I guess not.
Do you know how import the two vent flaps are in the boot? Is it just there to relieve pressure when we shut the doors/boot?

 

[Silverspa]

Hello All.
There are a few smelly AC posts on here, however this one seems different.
With the AC switched On, eveything is OK, no humidity or smells. Once I hit the EC button (AC OFF) the windows mist, the air is very humid, and it starts to smell.

Other then the obvious, leaving the AC on all the time, what could I do to fix this, and what could be the cause?

MB suggest a AC service, he said they check the drains are clear, change the combi filter under the glove box and run a fungus killer through. Just over £200.
Should i just pay up ?

*Someone suggested a leaking Heater matrix. But im not loosing coolant and I have only just last week re-fitted all the carpets, so I know it was not soaked down there.

Its a W203 C270CDi

Good luck with this, I just had my a/c regassed by a local indie, and since I have noticed an intermittent smell like stinky old socks (eww!) when the a/c is switched off. I thought it might just be dirt dislodged in the system and that it would clear after a while so blasted the fans with the windows open. Went away for a while but keeps coming back...think I might take it back to them...:neutral:

 

[HelpThisDude]

Hello Silver Spa, I'm going to give the car to MB to check over the vents, do some anti bacterial spray through the system, and have a re-gas. They charge £99 for an air con service- More if you have an extra charcoal filter (My car, as it turns out, does not).
I will have this done Monday morning, so I will report back later in the week and let you know if it has fixed the smell/humidity.
Someone has suggested checking the vents in the boot. They only let air out, and not in via rubber flaps. They are hidden between the rear lights and the rear arch, behind the trim. Mine might be obstructed because of the way my amplifiers sits against it (almost embarrassed to admit I have amplifiers).
So all of this might be my own doing - but I doubt it.

 

[HelpThisDude]

It’s worked.
Smell has gone everything back to normal.
£99 + pollen filter which they say was dirty, I didn’t think it was, but I’m not that bothered- I can breathe again
Thank you all for the input and advice.