miatafile

Anybody had the nerve to give this a go on there own? My Father-in-law's '03 C240 was just diagnosed as needing an Evap replacement. Will not hold a charge, and the usual $2.5 - 3k was quoted.

Any major show-stoppers to giving this a go ourselves? I know we are looking at pulling the dash, airbags, etc. We'd of course only be replacing parts and leaving evac and charging to a shop with the requisite equipment. There is no charge in the system to recover, so that is not an issue.

I'm an accomplished shade-tree with much experience in engine, suspension, and transmission work, but have yet to replace any a/c components. Thoughts?

Thanks, Paul

mleskovar

Go for it. Airbags should stay as far as I know. There's several DIY posts about replacing the air flap actuator arm and the evaporator is right behind it. Search on 'stepper motor'. Replace those arms while you're at it. There's a couple gotchas so follow the instructions carefuly. The first time is always the hardest, hope you won't need to do it more than once. Good luck.

Moviela

It is a big job to tear down the HVAC system to the point of changing the evaporator. Before I did that I would like to see with my own eyes why the core is not sealed. Since the system is empty, I'd isolate the core and pull a vacuum overnight, then close the valves and look for it to hold vacuum for several hours. If the gauge does not move, I'd pressurize the core with nitrogen to about 80 lbs, close the valves and look for any movement of the gauge. Failing either test, its time to get out the Torx tools and set cracking.

If the isolated core holds vacuum and pressure, you need to look elsewhere.

You may be in for a shock if the system has been open to the air for longer than a brief period of time. Air (the Oxygen part) and moisture will corrode the metal parts quickly. A blackened aluminum oxide can form called the "black death" because it kills everything in the system touched by the R-134a and oil. Some very specialized shops have flushing equipment that can clean the lines, but usually the compressor and expansion device should be changed. The receiver drier can become saturated with moisture in as little as an hour of exposure to the air. It must be replaced when the compressor is replaced.

Here is some training materials to aquaint anyone with Mercedes HVAC. This is for the 211, but the 203 is very similar.

http://www.mercedestechstore.com/pdf...2008-30-02.pdf

C230 Sport Coup

How to remove the dash....

https://mbworld.org/forums/c-class-w203/177068-noisy-air-conditioner-stepper-motor-replacement-clicking-hissing.html

ohlord

if it's easier than this You should have no problems.
http://www.mercedesshop.com/Wikka/W210Evaporator