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water pump pulls coolant in through the lower rad hose, pushes through the block, into the heads, into the intake, against the t-stat, t-stat opens, coolant goes to rad

as for heater, coolant goes from the intake(higher pressure due to restriction of t-stat) through the heater control valve, through the heater core, then back to the rad

the heater control valve will also bypass the heater core when the heater control is set to cool, then send the coolant from the intake to the heater core outlet tube(metal, along pass side frame rail) that goes to the rad



there is also an internal bypass(only 3/8) that feeds a small amount of coolant from the right (pass) head, through the block, into the water pump(this is the hole below the bottom bolt hole in the pass sibe of the water pump)

 

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actually, if the t-stat is closed, and the cap is off the rad, it will force water into the intake and through the engine backwards

 

I'm attempting to use the Prestone flush kit as well. The instructions indicate attaching the flushing T to the heater core inlet hose coming out of the firewall.... There are two hoses! Any idea which one is the inlet hose. Closest to the fender or engine block? I've gone through both my Chilton's and Haynes.... neither one indicates which hose is which.

 

One of the heater hoses runs down the firewall, along the front frame rail and connects to the radiator. This is the return line.

The second heater hose runs along the passenger valve cover to the diverter valve, then to the intake manifold. This is the hose where you will install the flush "T".