[Christoph]

Thanks for answer.
i guess i need a new radiator anyway.
Tried to clean mine as stated somwhere else by Tom Wesenberg.
Water is clean an not greasy anymore, but radiator seems to be barred somewhere.
difference between Top and Bottom of radiator is about 10 degrees
and it likes to go hot.
Will have to take it out to do this "4-second-drain-test"
Best regards Christoph