I have a 1983 Porsche 944 and need to change the heater hoses. I am unable to locate the heater hose connections to the heater core that are located inside the passenger compartment. In the Haynes manual for Porsche 944 (80035(1027)) there is no removal and installation procedure for the heater hoses that enter the firewall, although the manual advises the hoses should be inspected and replaced periodically. Any advice would be greatly appreciated. Thank you