Both of the bypass hose nipples on mine were not only white with corrosion but deeply pitted.
I wire brushed and pick out all of the white corrosion and filled in the pits with JB Weld (the slow curing one that can take the heat).
That was back in 2008 and have had no issues in that area.

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84 300D, 82 Volvo 244Gl Diesel