W123 air conditioning upgrade
When I first bought my 1981 Mercedes 240D, the A/C did not work. It was apparent that the car had been siting around for a while, so it was not really surprising. What was surprising, was that it worked well when I had it gassed up. When cars are advertised for sale as just needing a re-gas, you know that they need a lot more than that. The gas had been retrofitted to R134A, as the caps were blue and red.
The A/C worked well until I took the car off the road for a couple of months to fix the fuel system. After that, the freon had leaked out again. A further re-gas and having the valves changed basically just gave me my road trip to Brisbane. Clearly there was a leak somewhere.
I looked with my blacklight, and the issue was apparent. There was green dye all over the compressor. This isn’t all that surprising. A/C compressors need to be run regularly to prevent leaks. As my car was likely laid up for a while before my ownership, the seals had obviously gone.
My 240D is new enough that it uses the GM ‘pancake’ style rotary compressor, not the York. My 240D still had the AC Delco compressor with metric fittings these cars came with. I do not believe these are available anymore. I bought an Omega brand compressor to replace it with. Naturally I had the drier replaced at the same time.
I could have stopped there but decided to upgrade the condenser too. The original condensers designed for R12 don’t work all that well with R134A. I’ve been very happy with the Klima Design works condensers in my 560SEC and 450SLC so decided to also put one in the 240D.
I noticed in the W123 instructions it mentions that you can paint the condenser black to match the factory look. I reached out to Klima Design Works to confirm that this would not impact cooling performance. Their reply indicated that their testing hadn’t seen any measurable impact. I decided to paint mine before I had it fitted.
It was a pretty easy job to paint both the condenser plus the various fittings satin black. I only painted the front of the condenser. The back is not visible.
I had the new compressor, condenser, drier etc fitted a couple of weeks ago. Painting it black made a huge difference in how noticeable it is. I’ll probably go back and see how much I can paint the condensers I have in the two 126s and the 107.
Its been pretty cold in Sydney since I got the car back. The new upgraded A/C seems very good, but I’ve not had a hot day to test it with. I’ll be doing a trip in January for the 50 years of the W123 event, so having nice cold A/C will be a plus for that event. While I don’t miss most of the features of modern cars, I do very much appreciate cold A/C and these condensers really help. I won’t know until it gets hotter, but so far I am happy with my W123 air conditioning upgrade.
While I don’t particularly notice it when driving, it is apparent when the compressor kicks on when the car is idling. The compressor is probably using a decent chunk of the power the OM616 makes at idle.
It is a complete bolt in kit so I could go back to original at any time. I don’t plan to though. I have kept the original one to go with the car.
