The original tank did not have the SCA pack in it, perhaps later 124 models did, I don't believe that my new dealer/OE tank that I bought/installed 5-6years ago has one.

If you install the proper HOAT coolant / MB-spec., and observe proper change intervals I suspect that you will be fine as this is a dry-sleeve engine and designed with the original configuration. If you are able to find a new tank, certainly I'd prefer (and did so) to install new OE.

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Gone to the dark side

- Jeff