Hose Question
 

I'm doing some simple maintainence on my '72 911. I'm doing the valve cover gaskets and was wondering what the fat rubber hose is on the drivers side of the motor. On both sides of my motor they are looking pretty old and want to change them out.
Thanks!!! Here's to some winter projects.

Pictures?

If you have mechanical fuel injection the fat hose on the drivers side connects heat exchanger to the mechanical pump for warm up purposes. If you are talking of the smaller oil hose off the side of the engine case connects to the oil tank. Need pictures.

After reading again, the two (2-3/4” off the top of my head) hoses, usually black corrugated ridged but flexible. Sometimes orange a more rubbery with a spiral wire in it. Those are heater hoses. They direct air from the fan housing to the heat exchangers and then the hot air goes forward in a second set of hoses to the body.