1994 Ford Taurus GL Wagon, 3.0L V6 regular engine (not flex fuel or
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?