water direction

[flatmotor40]

When water comes out of the head which direction is the water going.I put a 90 degree elbow on the back of the pass head to run to the Vintage air Heater box.No A/C.I have a hard ime getting hot water to the heater itself.I have a line going to the lower pass side radiator hose.Does water go from that hose to the heater core or does it come from the heater core.Thanks

[Lawson Cox]

Water comes out of the head and is pumped upward to the top tank on the radiator, and then runs down through the radiator to be cooled. You want to hook up your heater so you are pumping water from the head into the top of the heater, letting the hot water run down through the heater core and out of the lower heater hose to the lower hose on the radiator. Capish?

[Ken/Alabama]

You got thermostats in your heads ?

[aussie merc]

Question what are we talking about a 60HP,21stud,24 stud or 8ba style flathead ?

[ford38v8]

Originally Posted by aussie merc

Question what are we talking about a 60HP,21stud,24 stud or 8ba style flathead ?

Doesn't matter. All the same. Think of the heater as just one more radiator to be plumbed in the same manner, just smaller. Hot water exits the head, goes to the top of (each) radiator, out the bottom of (each) radiator to the lower hose and re-enters the block.

[flatmotor40]

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During the summer I take them out but I will put them back in now.But this has been doing this for some 6 yrs not getting hot enough to feel the heat from the heater

[Mart]

Do you thing the heater might need flushing out?

[Pete pa]

It may have an air lock in the heater core. If your vintage air unit has the pipes one above the other coming thru the firewall, connect the head hose to the bottom outlet on the heater, and the top hose of the heater to the lower radiator hose.

[JayChicago]

I always heard that heater hoses should go input on the bottom, outflow on the top. This to let any trapped air get pushed out by the water flow. go with the flow. But I have to say I don’t know if there is any validity to that.

[Fritz]

Originally Posted by JayChicago

I always heard that heater hoses should go input on the bottom, outflow on the top. This to let any trapped air get pushed out by the water flow. go with the flow. But I have to say I don’t know if there is any validity to that.

I’ve seen that advice here several times also.

When I replaced the hoses, I gave it the “extra radiator” routing that ford38v8 advised. Hot water in the top, and out the bottom. Made sense to me. The heater core heats and the engine cools very well.

[Flathead Fever]

At the phone company, where I was a mechanic for 30-years, when a driver complained of no heat it was aways one of three problems. The most common problem was a slightly stuck open thermostat. In the winter, the engine won't reach operating temperature if the thermostat is just stuck open a little. The first thing you do is look at the temop gauge to see if it is reaching nornal temperature. Then touch the upper hose to make sure it's hot. The least common problem was the hot water shut off valve to the heater core. Most cars don't have them. They are comptroller by a cable, or a vacuum operate valve. When they fail to open, hot water does not reach the heater core. A fairly common probelike was a plugged heater core. The way to check it is to grab the two hoses, one will be hot, and one will not be. That tells you no coolant is flowing through the heater core is. Determine the direction of flow, the hot hose would be flowing into to core. Remove the hot hose from the heater core and the cold hose from the engine. Take a garden hose and reverse flush the core through the cold hose If you are lucky, you can unplug it. I have seen mud come out of them like tooth paste and then they work fine again. The heater core is not designed for garden hose pressures so start off with the least amount of water you can.

As far as the direction of flow through a heater core. I had very smart neighbor with an engineering degree. I know he was smart because he moved out of CA to Tennessee and left me behind here. He was the head engineer at a million-sf cold storage refrigeration plant. We had this conversation about the direction of flow through a radiator. He said, if you want to cool a radiator core you flow the liquid from top to bottom. If you want to heat the core you flow, it from bottom to top. I have early Mustangs too, so I use a lot of illustrations from them to explain things. These are 1965 Mustang heater hose routing illustrations. The hot water is flowing out of the intake manifold and back into the suction side of the water pump. Notice the hot water hose from the intake manifold flows into the bottom of the heater core. The opposite direction of flow than the radiator.

[petehoovie]

[Pete]

A STOCK flathead Ford V8 will cool more than adequately with the stock cooling system configuration.
Heaters go in parallel with the radiator. Easy to remember like wiring batteries in parallel or series.
As long as the cubic inches are not increased some mild
engine modifications will not overload the cooling system.
Increase the cubic inches by 50 or more and usually there is a cooling problem.
If you can deal with the plumbing problem, running the cold water into the hottest part of the engine FIRST (heads) will result in better cooling. This dos not necessarily mean reversing the water flow in the whole system. Sometimes that won't work due to air pockets.

[aussie merc]

basically hot water into the heater will come out of the engine, between the waterpump and the thermostat [using water pump pressure] and return to the engine as close as practicable to the water pump draw [IE] bottom hose.