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Hayne's manual sucks

Hey all you cooling system gurus,

I have a 96 Ford Taurus GL and I'm trying to trace the coolant flow in the system so that I can understand the path it takes with

#1) the thermostat open

#2) the thermostat closed

The hayne's manual is very brief and doesn't really explain it very well so I took a look under the hood and tried to make as much sense of it as I could myself but I am still confused in some ways. But here is what I think I understand.

There are 2 parallel radiators stacked one in front of the other. The bottom hose comes off and branches into a "Tee", letting the smaller offshoot go to the bottom of the pressurized expansion tank (no pressure cap on the radiator, it is on the plastic expansion tank/overflow tank). The larger offshoot appears to feed upwards into the engine block.

Now, I notice that the water pump does not appear to have a hose inlet so I guess it pulls water directly out of the engine block. However, the water pump outlet goes to the firewall to the heater core inlet and the heater core outlet goes to right behind the thermostat housing. Then right near the thermostat housing a hose is connected that goes under the air intake manifold and leads to the plastic expansion tank.

So the plastic expansion tank has 3 hoses that connect to it, 2 small ones at its top and a bigger one on its bottom. How all this stuff works is very confusing because I know I can't just call up my local auto parts store and ask.

I really would like to understand how the coolant flows when #1 and #2 are the case. Any takers?

The 2 parallel radiators, how are they connected, if they are, for extra points?

Gracias.

Reply to
August
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"August" wrote

Ford...I don't usually do those beasts (grin)

You only have one radiator, the other one is the A/C condensor. The bottom hose you see is the "return" or cold(er) water hose from the radiator up to the rear of the water pump. Note: some of the passages will end up being internal in either the block, or front cover (wherever the water pump is mounted). The hose that tees off up to the overflow reservoir is simply a way to get the coolant from the overflow into the system.

Here, you just have the heater hoses backwards. The heater hose inlet always comes from a pressure point in the cooling system which usually somewhere at the intake manifold. This matches up with the hose that you say goes right behind the thermostat housing. The heater oulet hose is the one that routes back behind the water pump, or in other designs it will dump back into the radiator.

The two small hoses are simply returns/bleed hoses back to the expansion tank from the cooling system. The larger hose dumps coolant into the lower rad hose which is a return back to the water pump.

You missed one hose, the upper rad hose should go from the thermostat housing to the upper part of one side of the rad. When the thermostat is open, the coolant flows from the intake manifold/thermostat housing, thru the upper rad hose to the rad, thru the rad to the lower rad hose, back up to the back side (suction side) of the water pump, thru the block and up thru the cylinder heads and back out thru the intake/t/stat housing. Coolant also flow in parallel to the heater core, pressure from the intake manifold area, returned back to the rear of the water pump.

Thermostat closed:.....the fluid is simply bypassed back thru the block and cylinder heads by a bypass passage that can be either a separate hose, or cast right into the thermostat housing/or intake manifold.

See above.

Ian

Reply to
shiden_kai

Thanks and I mean alot.

Reply to
August

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