Only the Oldsmobile heater hoses can provide the conduits to bring the heated coolant to the passenger compartment. The diameter of the heater hoses are only about an inch, but the flow of coolant through them is necessary to provide heat to the heater core so the passenger compartment can maintain a warm temperature. This supply of heated coolant through the heater hoses on your Oldsmobile is also functioning when the defroster is on, so the amount of moisture in the air being blown on the windshield is reduced; eliminating the fogging effect water vapor has on a cold surface.
There are at least two Oldsmobile heater hoses on every model that was manufactured. There is a supply hose going from the engine to the heater core. There is also a return hose going from the heater core to the radiator or engine block. This is the flow pattern the heater hoses on for your Oldsmobile.
The heater hoses are constructed from a reinforced polymer that is built to withstand the rigors of the variation in heat levels they will encounter while an engine is operating. Even with the extra reinforcement, the hoses will lose their integrity over time due to the extreme heat from the coolant that will have to flow through them. Because of this they will be prone to developing a leak eventually and be in need of replacement. This leak generally occurs on the heater core supply hose where it is attached to the engine.
This will be indicated by a puddle of coolant under the Oldsmobile engine when the vehicle is parked. If this situation is not addressed, coolant will continue to leak which could cause the engine to overheat and damage the engine.