Before this gets further out of hand, someone please post a EPC pic of the driver side ( USA ) heater hose from the back of the head , to the bulkhead fitting and to the heater core. Also on this bulkhead fitting is a small hose that I think runs to the heated washer fluid bottle.

I just looked at my 97 E320 parts car ( in the dark and rain. ) This is not a dash out job as the part in question does not go into the passenger compartment. It is a bit tight for space and likely requires the plastic at the base of the windshield be removed.

Be sure to order a heater hose that goes from the cylinder head to bulk head fitting , bulk head fitting. The hose from bulk head to heater and the small hose that runs to the heated washer fluid likely can be off the roll straight hose.

In any event this isn't an expensive repair even if a competent shop does it. I'd peg it at 2 HR tops.