A hat trick of questions today.

Can someone please tell me how the wire from the coil to the distributor is routed on an M103? Mine goes over the the thermostat housing and there are white scuff marks on the wire and a shiny spot on the aluminum housing indicating some arcing. Is there a wire separator or some such device that's missing. The wires were last replaced by the dealer.

Thanks,
Sixto
91 300SE
81 300SD