I had a similar colored liquid in my bilge. after a long search it turned out to be the red gear box oil mixed with diesel. reason was leaking gearbox and leaking diesel hp pump. fixed both and all is fine now.
you might also want to check on the heat exchanger lines if everything is tightened properly.
what does the liquid smell / taste like?
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Bernd
SN 119 / Cascais, Portugal