Intermittent Air Con

[GGB]

Thought somebody might be able to diagnose the fault I've got with my w202 c220 cdi air con? The symptoms are very low air flow (even when selected to max 5) but the system seems to be very noisy without accomplishing much, also the output sometimes fluctuates without anyone touching the controls. I've tried re-circ and this marginally improves matters, however with the outside air temp. hitting +30ºc the situation is getting desparate!

 

[Blobcat]

If the fan is running and the speed varying (with the switch) yet very little air coming out of the vents your vacuum system could be faulty. If you alter the air direction switch can you hear the flaps moving around?

 

[GGB]

Hi Blobcat,
The airflow direction switch seems to operate correctly, although i can only just hear the flaps moving over the fan.

 

[Blobcat]

OK, if the EC switch is off and temp set to max cold, does it get cold?
With lots of noise and very little air you could have an AC problem (no Gas). Open the bonnet and check that the compressor starts and stops when the EC switch is pressed. If it doesn't start then you are out of gas. Find and AC specialist and have then do a leak test and re-gas.
Changing the polen filter (depending upon when it was last changed) is also not a bad idea.

 

[GGB]

It does get cold...just not a lot of it! I will try your suggestions on the compressor and the filter (just a quick question though...where about's are they both? Obviously the compressor is under the bonnet somewhere, but as to the pollen filter??? I was considering getting the system re-gassed soon.

 

[Blobcat]

For the pollen filter pls see the attached;
http://forums.mercedesclub.org.uk/showthread.php?t=19061&highlight=pollen+filter
The compressor is on the RHS of the engine, failry easy to spot, solid aluminimum pipes running to it.

 

[GGB]

Jackpot! Thanks Blobcat I will get on the job this afternoon. I will post a reply to tell of my (hopeful) success!

 

[jberks]

I don't see how regassing would help. That's only relevant if the aircon isn't working or not getting as cold as it should. From your description, the aircon is fine, but the ventilation system isn't. Also, if it's noisy, then the fan is fine too. So, either you have a flap actuator problem (rare but possible) or the filter is blocked - more likely. I'd start by replacing the filters.

 

[GGB]

Bang on! I replaced the pollen filter (Obviously not been done in the recent past (I've only had it 2months!)). Everything is now A1, thanks to everyone for their responses, as always v. useful!