This is the path of coolant through a warmed-up V6 Tracker engine. Note that all the coolant pipes and hoses converge at the thermostat housing.
If the thermostat is open, the coolant passes through the radiator and returns to the water pump. If the thermostat is closed, coolant does not pass
through the radiator and instead is recirculated inside the engine block.

This is a block diagram of coolant path through the V6 Tracker engine.


This is the water pump for the V6.


The water pump is located in the middle of the engine block.


This is the water pump opening in the block.


The water pump forces coolant into the block and out around the cylinders and then up into the heads.


Most of the coolant exits out the back of the heads. A small amount exits out the front
of the heads through left and right bypass hoses.


The coolant exiting the rear of the heads is captured by the water crossover pipe. The
crossover pipe has three outlets. The main outlet is the return pipe to the thermostat
housing. A smaller hose directs hot water to the heater core. Another hose directs
hot water to the throttle body. Eventually all three paths meet back at the thermostat
housing. If the thermostat is open, coolant flows through the radiator. If the thermostat
is closed, coolant is internally bypassed back to the water pump.


The hot water through the throttle body melts a wax pellet in the fast idle-up system.


The wax pellet pushes a rod which actuates a cam that
slightly opens or closes the throttle plate. When the wax
is cold the throttle opens just enough to force a fast idle.
As the engine comes up to temperature, the wax melts,
the throttle plate closes and the idle is reduced. None
of this requires a PCM input (through the Idle Air Control).