w210 coolant hoses collapasing when engine reved

[speednjay]

99 e300 td

i noticed that the 2 small coolant hoses are collapsing when i was reving the engine in the driveway. the one from the electric pump to the engine and the electric pump to the duovalve. everything else seemed to be normal.

any ideas what would be causing it? the hoses seem to be in good shape. i did buy new hoses but they seem to be as soft as the present hoses.