1948 Heater Hose Routing Question

[48Super]

I've seen low mileage 48's with two different versions of heater hose routing and I'm wondering which is correct or if a change was made during the model year and both are correct.

The first version (shown in the shop manual for 1948 models) is as follows:

1. Hose from the lower connection on the engine thermostat housing to the upper connection on the heater control valve on the firewall.

2. Hose from the lower connection on the heater control valve to supply the heater core under car.

3. Return hose from heater core to inlet of defroster core.

4. Hose from the outlet of defroster core to upper connection on engine thermostat housing.

This is how my car's hoses are routed as shown in the picture.

The second version (similar to that shown in manual for 1949) is as follows:

1. Hose from the lower connection on the engine thermostat housing to the upper connection on the heater control valve on the firewall.

2. Hose from the lower connection on the heater control to supply the defroster core. A special "U" shaped molded hose is used, see picture..

3. Hose from the outlet of defroster core to supply heater core under car.

4. Hose from return on heater core to upper connection on engine thermostat housing.

I think the second version of the hose routing using the special molded hose was standard from 1949 through the early 50's and I'm wondering if some earlier models were modified because it was thought to be a more efficient arrangement for water flow. I'd appreciate any thoughts or information on this. Thanks!

[Guest clintons garage]

Hi, i have a 49 special and my hoses are set up as per the second method u describe. I cant coment on efficiency as i am still working on cooling system following a blocked radiator.