Benzmac or MBDOC has posted that they have to flush out the cooling system repeatedly with a citric solution to get rid of all the traces of oil.

I think it was Donnie that made the post. He said it's real hard to get rid of all of the residue.

Hopefully, that's your problem...

__________________
Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".