Hi all!
The airconditioning in our 93 E220 just died. Got it checked out and was told the "non return valve" has to be replaced and it will cost A$800 plus.

Can someone please help explain what this is and I assume it is not one for DIY? I am quite good with basic mechanics, but I guess this is something else.

All comments/feedback very much appreciated.

I have not heard of that part, but it might be what we call the Expansion valve. If so, I would not do it at home. I would have it done by a pro.