351c 4v heater hose routing..

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cazsper

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Location
Sunnyvale, CA
My Car
1968 Coupe: 393w, TKO-600, Maier Racing springs, Global West suspension, Currie 9in with forged axles, 3.50 gears, Trutrac, Baer brakes front/rear
1973 Mach-1: 351c 4V, C-6, 3.73:1 gears and a long "To Do" list..
So- I have a '73 with a 4v 351c. I just got some cooling issues taken care of and now I want to tackle the heater. I have one hose that goes directly from the block to the heater core. The water pump actually has two ports but one is blocked off. And of course, the other port is connected to the other inlet/outlet of the heater core. Is this correct? After driving the upper radiator hose is too hot to hold but the heater hose is just warm. And when I turn on the heater or defroster, it's just ambient temperature.

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The hose that is connected to the block is the pressure hose and should run to the inlet connection on the heater core, which is the one on the lower left. The hose connected to the water pump is the return line. If the hoses are connected wrong there will be an air pocket in the heater core that will prevent coolant flow through it. The other possibility is that the heater core is plugged, which is not uncommon. You can check the heater core by either removing the return hose and running the engine to see if coolant flows through it or by blowing 15 psi air through it. Don't connect a garden hose to it, the typical 30+ psi water supplied by your utility company is likely to blow a hole in the core.

 
The hose that is connected to the block is the pressure hose and should run to the inlet connection on the heater core, which is the one on the lower left. The hose connected to the water pump is the return line. If the hoses are connected wrong there will be an air pocket in the heater core that will prevent coolant flow through it. The other possibility is that the heater core is plugged, which is not uncommon. You can check the heater core by either removing the return hose and running the engine to see if coolant flows through it or by blowing 15 psi air through it. Don't connect a garden hose to it, the typical 30+ psi water supplied by your utility company is likely to blow a hole in the core.

Thanks for the reply. I'll check that this afternoon..

Mike

 
The hose that is connected to the block is the pressure hose and should run to the inlet connection on the heater core, which is the one on the lower left. The hose connected to the water pump is the return line. If the hoses are connected wrong there will be an air pocket in the heater core that will prevent coolant flow through it. The other possibility is that the heater core is plugged, which is not uncommon. You can check the heater core by either removing the return hose and running the engine to see if coolant flows through it or by blowing 15 psi air through it. Don't connect a garden hose to it, the typical 30+ psi water supplied by your utility company is likely to blow a hole in the core.

Thanks for the reply. I'll check that this afternoon..

Mike
Just took a look at the hoses.. apparently, they are attached to the heater core in reverse. I'll swap them around after the rain subsides and see if that helps.. thanks again..

Mike

 
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