Air con leak C220 cdi est.

[PML]

I have established that I have a very small leak in my aircon.
so small that it is undetectable.

My Ac is getting warmer over about a month, to the point of only blowing warm air.
last time my eco, button kicked in to prevent ac use.

I have had my aircon re-gassed twice now and the eco reset, a flurecent die inserted but the leak is not materialising uder ultra violet.

It is obviously a very small leak.

Any suggestions on how to resolve this or maybe where it could be.

a very warm

PML

 

[lynall]

I would always look at your condensor radiator first, mainly for stone damage.
Mine had mutiple small holes 2001 y plate



Lynall

 

[BlackC55]

+1 for condensor.

 

[kwakdonut]

Yup, agree with that. Mine went on my C270 - a common problem

 

[jaymanek]

If you cant see the dye it would be worth taking the underpanels off to check the leak is not under the dash...

We have had a few W203's through with leaks at the evaporator under the dash... not a nice job.

Of course condensor is always the most common but not always the cause.

 

[aircondoc]

I'm not familiar with your model's aircon but a few general principles apply. Try looking for the dye under the evaporator drain (where the water drips under the car) and if possible split the radiator and condensor and look down between the two. Check around the compressor shaft seal, usually a garter type that works better when lubricated (hence the "use it every week" advice). A lot of the pipework is aluminium and corrodes, sometimes where the 'O' seals sit. I can't believe a car losing it's gas after a month isn't showing under UV. Tiny leaks can be fixed with "Leakstop Pro" but you need a specialist to put it in as it goes in when you regas. I haven't done this work for a couple of years but i found UV dye the best leak detector on cars, especially in the inaccessibl bits although my electronic detector can find a leak of 11 grams/year (you're losing about a kilo a month depending on the charge) and is great when used in conjunction with a Nitrogen pressure test. If he has one of these sniff in the air vents with the fan running. These are just a few ideas, I hope they are useful.

 

[cleverdicky]

You need to establish two things (assuming you cant find a dye stain).
If you can, CAREFULLY have a feel of the two pipes along side the engine bay just before they disappear towards the rads. The narrower of the two, is the liquid line and should be barely warm. The other bigger one should be WARM if not hot, if not bloody hot. Or better yet use an infrared thermometer.
If they're both stone cold you have issues! If the larger one is quite warm then your ok. If VERY warm, you still have issues but may indicate over charge or air in the system. (air doesn't condense so wont refrigerate but will still get hot and raise the system pressure)
Do you have a sight glass fitted anywhere? If so look for a few bubbles.
An option would be to let the gas go, and take it back. Can you get access to a set of gauges?