Best Way to Flush AC system?
 

As I mentioned in another thread, I just changed the compressor on my 380sl. But, afterwards, when I evacuated the system, I turned the vacuum pump off and left the ports in the manifold gauge open. So, app. 100cc of oil from the Mastercool vacuum pump got sucked into the system, because the pump didn't have a valve to prevent that from happening.

Anyway, as I now have to take the system apart, and flush it, I was wondering if I also have to flush the evaporator coil which, if I'm not mistaken, requires removing the expansion valve first.

So, I was also wondering if anybody has ever done this on a 107 and, if so, how difficult it was.

Thanks in advance.


Bill

I can't speak to the 107 particulars, but if that pump oil got into the evap or any other part of the system, it's going to need to be removed. I am no expert on MB systems but as I recall from my way back US made auto aircon experience, keeping the system oil in as pure a state as possible is very important. Also, there should be no oil where none is intended.

You must remove the expansion valve. I usually undo every connection and flush each component individually. Flush until you think it's clean and then flush again. Replace the o-rings, park it in the sun and pull a vacuum to evacuate the system with a good pump with new oil. Be sure to replace receiver/dryer.

I use this flush tool now:

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I believe acetone is also a pretty good flush agent for this purpose.