I need advice on replacing the evaportator core or how to save some $$$! I've had my 2000 C230 in to the shop twice. Freon in leaking out over about a 3-4 week time frame and no leak is being detected. Recommendation was that it is leaking from the evaporator core and cannot be detected because it is buried up behind the firewall in the dash. Has anyone else experienced this or have any advice?

Thanks

 

First of all you don't have Freon you have R134a. I am suspect about what you were told. You can but a leak detector kit yourself at any auto parts store. Buy the one you don't need the yellow glasses. I used a R134a recharge with a purple dye, found the leaks in seconds. I was lucky it was a loose low pressure hose on my W107.If it is the core, this job is best left to an expert.

I find it odd the evaporator core is leaking, as it is under the dash, my 99 W202 has the same set up and the AC is fine, especially since it hit 103 yesterday and today might get to 106. Being under the dash is sort of a protective measure from the elements. Have you changed your cabin filter lately?

IMHO you could have a a tiny leak in a hose or the filter in the condensor/ dryer could be clogged, this would cause poor performance. These filters are DIY jobs and if you live in a warm climate year round, the filter in the dryer would have a shorter life span, then folks like me who live in New England.

The condensor/dryer is under the hood mine is silver metal and located on the drivers side up toward the radiator. It is a circular device and the sight glass is located in it. On my W202 it is a bear to get to. On my W107 I installed a new one in about an hour, as it sits right next to the aux fan and easy off and easy on.

Access to the filter on my W107 was to take off the pressure switch and it was a pull out and push in deal. Sorry don't have a clue on how to change on the W203's

 

Each time I took it to the shop the R134a was 1.5 lbs low the first time and .5 lb low 3-4 weeks later. Must be a leak somewhere I would think but the filter could also be an issue I suppose.

 

I had the misfortune of replacing the evaporator in a 3 series BMW once. I think I used every tool known to man and then some I had to MAKE to get to that dern thing. It is buried up under the dash against the firewall on the interior. I took out seats, yes, the seats.....the console, the steering wheel and column (which had special security bolts holding it I had to hack off), the entire dash, including gauges, AC vents, glove compartment, carpet, you name it.....it was piled up in my garage. Oh, yes. The radio and CD player (same thing).....and every electrical connector the car had from the front seats forward. And I'll bet you're wondering if I fixed it. Right? Uh huh, but you know that saying, "NEVER again???"...............never never again. For any amount.
I think I still have the scars from the job.[:@]