CLK 208 air con problem

Had my car regassed at the end of last year maybe October time by a mobile specialist. He assured me that there were no leaks in the system. Gas lasted a few months when the car started hissing again I think in March/April on initial AC startup. So I called him back - he had put in the dye when he regassed it but again could not find any leaks under UV inspection. Its now again doing the same thing so there is a leak somewhere but again I tried to look for it with a UV light but no luck - the only thing florescing was the duo valve - is this normal? Any advice of where to look for a leak or what to do next?

 

Not easy this one, and the duo valve is not part of it. This could be the evaporator leaking in the heater box, but this is hard to check, it is in a very close proximity to the heater matrix and water in the duo valve but I cannot think that this could be the tell tale

 

Thanks. Do you have a copy of the air con/heater diagram?

 

W208 Air Con

Not trying to hijack this thread but thought I would keep it as I have a similar problem. W208 climate control, no cold air, EC light stays off. Car was regasseed (topped up) 2009 according to service records. Bought the car Sept 2010 and probably never really needed a/c until recently! Tried turning on ignition, holding rest and filter switches down for 5 secs. This gives zero on the left hand display which I can toggle up and down from 0 to 15 (not temperature reading.) Does not change any other display or show any fault codes etc. Tried to reset but don't really know what "pop out left auto vent button and right auto button means" Can only push auto controls on far left and right of unit. Perhaps I don't need to reset as the light doesn't come on?
Is there a sequence of tests one can do to try and isolate problem. My local garage will re-gas but it would be good to have an idea if this is the problem and surely should last for more than 2 years? Finally my windscreen fitter said a/c should be run at least once a week but I thought this applied to earlier cars (1999). Any thoughts.
Thanks

 

AC should be left on all the time - really useful in the winter too as keeps the screen from misting up by dehumidifying the air. This also allows the seals to remain lubricated so you don't end up with a leak. Saying that, I still have one somewhere!

 

zedmeister - Do you have the climate option and if so have you tried "playing" with the controls to check any fault codes etc . Not sure if there is anything you can do if a/c. Agree re misting up etc. and I should add my EC switch seems to work as prescribed i.e. goes on and off when pressed. It might help others if you put your location in your profile unless it's top secret. Who knows you might live up the road to someone!

 

It is the cars like yours that do need to be run every few weeks, you have the clutch type compressor, the main change was not till a year later on new models. If you have the lamp on all the time on the EC button then this can only be activated on STAR after a re charge

 

Malcolm, no lamp seems to be doing what it should although I don't seem to notice any change in sounds when I press it on (lamp on) or off. Should I take it to the garage and get it re-gassed (checked) and reset? Nothing I can do with the climate control re pressing auto vent buttons etc.
Boy how true your signature is. My remote stopped working and I tried the manual key to get into the boot to no avail. This one is truly for the delicate touch! Much WD40, extremely gentle turning again and again (about 25mins worth) until it freed and turned. Did not appear to be anything wrong just finally stuck itself. Now I do it once a month.

 

I think that I would go to kwikfit where they do not charge if the re fil and it does not work, you do need to know what is in there before anything else.

You should squirt some PTFE into the lock and it will all go silky smooth and last, spray some on your front door key and lock and it will all work so easily, do the piece that comes out of the lock into the keep as well

 

Yes I do - how do you go into it and is there anything useful? Seems to work okay when gassed, just leaks out over a period of months. The hissing on startup just seems to get more and more as the compressor tries to compress less and less gas. Added my location - thanks!

 

Long thread here
http://forums.mercedesclub.org.uk/showthread.php?t=27407&highlight=Pop+left+auto+vent+button&page=10
posts no 31 and 94 pick up on resets. On mine if I press recirc and rest for 5 secs I get 0 on the left panel and lo on the right. If I press left auto switch up and down I just get 0 to 15. If I switch off and on then press defrost and rest I get numbers all over the place. I assume there is a way of resetting but can't fathom it out. See my previous post in this thread. It may be nothing to do with the problem but it would be nice to know how it all works. I have tried recirc and defrost to no avail.

 

Not sure if anything will help in there as the gas is probably low again - it had to be topped up last time. I don't think its a sensor, etc issue.

 

Yes there is means on the control unit to test it all, I cannot do it or put it up for a few days

 

Booked in at my local garage tomorrow morning I will let you know how I get on. Thought about Kwik-Fit called their 0800 number and got a branch in Sterling who told me to look up local branch number, which I did. Called them got a response and then a lot of shouting at a customer then an apology for the outbust to me. Something in my head told me not to bother so I put the phone gently down. I am sure there are a few good technicians at Kwik-Fit but I've never found one.

 

Thanks Malcolm. Managed to find some codes and my 2002 CLK W208 picks up the sensor readings etc by switching on ignition and then pressing the rest button for greater than 5 secs. Then each sensor can be read with the auto button. Sensor codes appear to be

01 In-car temperature sensor.
02 Outside temperature sensor.
03 Heater core temp, left.
04 Heater core temp, right.
05 Evaporator temperature sensor.
06 Engine coolant temperature.
07 Refrigerant pressure in bar (e.g. '4' is 4 bar).
08 Refrigerant temperature.
09 Not used.
10 Heater blower control voltage (normal 08-6.0, meaning .8 to 6 volts).
11 Emissions sensor voltage (to detect atmospheric gases and recirculate interior air).
12 Sun sensor voltage (to shift airflow in car).
20 Control current for auxiliary fan (electric fan on radiator, given in milliamps or mA).
21 Engine speed (x100).
22 Road speed (km/h or mph depending on installation).
23 Battery voltage at terminal 58d (as a percentage of total voltage, e.g. 99.0 = 99%).
24 Battery voltage (e.g. 12.8 = 12.8V).
40 Climate control software version.
41 Climate control hardware version.

but I'm sure there are derivatives.
To get to the diags I set left to high and right to low and then within 20 secs pressed EC and Rest together for about 5 secs. Screen goes blank then pressed right auto to get error codes. Mine was just E on the left pane and FF on the right, which I understand, means ok. However, on the sensor codes my 7 was 0 indicating I had no gas pressure. There does appear to be different ways of getting diag codes so you might have to search around. I assume the diag codes may well differ per model knowing Mercedes.
Still I thought the sensor codes particularly number 7 might interest you.

If anyone has any "formal" data it would be useful.

 

Hi,
Take look at this link it tells you how to reset your systems fault codes.
Start from step 3.
http://ww2.justanswer.com/uploads/eurotec/2011-05-08_174253_air_conditioning_fault_codes_w210.pdf
This should preclude any need to plug the car into diagnostic equipment.

 

Ok in Garage this am and regassed and dye added. Short run and now getting cooling. Refrigerant Pressure in bar on Climate control code 7 is 8 I assume bar. I suppose just see how quickly this goes down. I assume it may vary slightly dependng on running, temp etc.

 

Hi Guys,

I was speaking to a Lady this morning who also has a w208 CLK. She has the digital climate control panel in her car. She said that it doesn't blow out any air at all hot or cold.

I wondered if any of you had any ideas what could stop the blower from working. Please let me know if you need any more information.

Looking forward to reading your replies

 

There are a number of likely causes

Water ingress to the motor causing it to rust up (blocked water drains - search on here for more info)
Heater motor bushes (new bushes can be bought quite cheaply from Ebay)
Fuse\relay

HTH

Dave