A heater hose broke, I'm replacing it, but I'm also trying to understand how my heater is working. I see that I have a heater bypass hose, so theoretically there could be a valve somewhere that cuts off flow throught the heater core, for example at full A/C. However, I can't find any indication that such a valve actually exists in my car. Could someone shed some light on this mystery? Why would I need a bypass route if the heater core is always on?
A brief explanation of what I gathered: Hot water exits the engine block and is then split into three possible routes: Radiator, heater core, and heater core bypass, as follows: If the engine is cold, the thermostat cuts the radiator off, so water can only go through the heater core or the bypass, giving first heat to the passenger compartment. If, however, the heater core is also cut off by a heater valve (electric, manual, or vacuum actuated), the water is circulated through the bypass only. Rather than halting all flow, a bypass eliminates hot spots while the engine warms up until full flow is enabled through the radiator.
So once again, in my understanding one needs a heater valve and a bypass, or neither, in which case the heater is always hot (but airflow is diverted past it if cool air is desired). Does my car have a heater valve? Where is it located?
Thanks!