39-40 hot water heater

[30-9]

Hey guys

The hoses going to the heater. Does it matter which way they go in?

Lower hose to lower connection on firewall & upper hose to upper connection or visa versa or no matter?

My heater is not putting out a lot of heat....

[petehoovie]

Hose from the head into the upper heater inlet....

[30-9]

Ok thanks. can anyone explain why it matters? I'm just seeking to learn.

[tubman]

As the coolant passes through the heater core, it loses some of it's latent heat, Cooler water is denser that warmer water so it wants to sink. Sort of like a thermo-sipho cooling system.

[petehoovie]

The water from the head is hotter than that from lower hose of the radiator....

[30-9]

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Thanks Gentlemen

[39topless]

Reverse in summer for AC.

[30-9]

Ok I went out to the garage (brrrrr cold out there) and it connected properly. Why would I only get cool air blowing out (with fan on)?

As for summer I have a shut off valve, but thanks

[petehoovie]

Do you have a valve at the cylinder head? Is it turned on? Did you let the engine warm up? Is the radiator topped off?

[40cpe]

Maybe the heater core is stopped up. Have you checked the flow through it?

[Brooks]

30-9 I sent you a P M about the diode wire.

[big job]

Old golden rule; bottom to top or top to bottom, which means bottom is water pump
that goes to top of heater and bottom of heater goes the top (head) ....

[30-9]

Guys yes valve is open and antifreeze is flowing through it as it should.

Am I reading "big job" post correctly he says hook up should be opposite of what everyone else described.

What am I missing too cold in MA need heat

[trainguy]

Thermostat?

[Terry,OH]

Follow the instructions that came with the heater.

[V8 Bob]

Originally Posted by big job

Old golden rule; bottom to top or top to bottom, which means bottom is water pump
that goes to top of heater and bottom of heater goes the top (head) ....

This ^ is how several vehicle illustrations show the connections, (like the ones below) and the layout I thought was correct for a '40 heater.
The one Terry OH provided isn't real clear, at least to my eyes.




Other diagrams show the exact opposite, like below.



I know the heater will perform better when connected properly, and cross vs vertical core flow may make a difference, so what's correct for a '40 heater?

[JSeery]

One way may be more efficient that the other, but the core is going to get hot either way and is going to provide heat. If the heater core is not getting hot then hot water is not flowing through it. Figure out the problem that is blocking the flow.

I would get it working and then experiment, try the hose connections with both arrangements and see how much difference it makes with the heating produced. Easy to check with a thermometer at the heater.

Looking at diagram Terry posted (which is difficult to see at the posted size) it looks like the lower hose goes to the top of the heater core and the head to the lower core connection. But again, this is NOT going to keep it from working or getting hot either way, just an issue of which is more efficient.

[hotcoupe]

Originally Posted by tubman

As the coolant passes through the heater core, it loses some of it's latent heat, Cooler water is denser that warmer water so it wants to sink. Sort of like a thermo-sipho cooling system.

i believe you should have said "sensible heat", 'latent heat" is a factor only when water as a liquid changes form either to a solid or a vapor.
tom

[JM 35 Sedan]

Originally Posted by JSeery

Looking at diagram Terry posted (which is difficult to see at the posted size) it looks like the lower hose goes to the top of the heater core and the head to the lower core connection. But again, this is NOT going to keep it from working or getting hot either way, just an issue of which is more efficient.

JSeery, when viewing those smaller pictures, click on them and hold the click in place until a drop down window appears. Then click on "open in new window" that enlarges the picture and even allows greated enlagment of that picture so you can see whatever you need to see. Much better than trying to view a small picture in some cases. At least this is how my computer and ipad work, not sure how your viewing system works.

Now, on the other hand, some folks here post pictures sooooo damn LARGE that they will not fit on the screen of my tablet, and are an even worse fit on my Droid (largest sceen available) smart phone. Sometimes these attached pictures are so large that I have to download them, and then downsize them, to be able view them properly. Not gonna mention any names here

[JSeery]

Yep, that is one method I have used. I normally save a photo to my desktop and enlarge them from there. This image does not enlarge that well for me to be sure of how the connections are made, are you able to enlarge it enough to tell of sure?

But it does look (to me) that the lower heater core hose goes to the head and the upper heater core hose goes to the lower radiator hose.

[mrfliboy]

Originally Posted by Terry,OH

Follow the instructions that came with the heater.

Is the original readable? Would love to get a copy of this. Same as the one in my truck. Too cool.

[JSeery]

Originally Posted by JM 35 Sedan

JSeery, when viewing those smaller pictures, click on them and hold the click in place until a drop down window appears. Then click on "open in new window" that enlarges the picture and even allows greated enlagment of that picture so you can see whatever you need to see.

Tried opening on my phone and it enlarges better on my phone! Still looks like the same connection setup to me.

[JM 35 Sedan]

Originally Posted by JSeery

Yep, that is one method I have used. I normally save a photo to my desktop and enlarge them from there. This image does not enlarge that well for me to be sure of how the connections are made, are you able to enlarge it enough to tell of sure?

But it does look (to me) that the lower heater core hose goes to the head and the upper heater core hose goes to the lower radiator hose.

Yes, I opened in new window, downloaded that into my tablet files, and when viewing that I can see everything very plain and clear on that picture. If I wanted to, I could then copy that using my computer printer. Easy Peezy

[37 Coupe]

On my 1939 Ford hot water heater but in my 1937 Ford I hooked up according to original instructions.Upper outlet which would be on passenger side returns to radiator hose. Lower outlet which is on or toward drivers side goes across front of carburetor to heater valve top of passenger side head. I think all of this is in 1939 book or an article Tom Cherry did years ago in V8 Times. Drake sells the proper heater hose clamps.

[30-9]

I kinda agree with jseery. I think it should work either way, but it's not.

My valve is open, I had the heater out last year and flushed it out. So cold up here temp gauge never hits 160 in winter months. I get (At best) luke warm air, nothing that will warm cabin.

I'm open to suggestions.

[ford38v8]

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Originally Posted by 37 Coupe

On my 1939 Ford hot water heater but in my 1937 Ford I hooked up according to original instructions.Upper outlet which would be on passenger side returns to radiator hose. Lower outlet which is on or toward drivers side goes across front of carburetor to heater valve top of passenger side head. I think all of this is in 1939 book or an article Tom Cherry did years ago in V8 Times. Drake sells the proper heater hose clamps.

This is correct, and in addition, trapped air must be purged before connecting the return hose to the pump hose nipple.

As an aside, Tom Cherry Jr was an avid V8er and one of the nicest guys in the hobby. His son Tom III continued with the heaters for a while but was more of a muscle car guy.

[30-9]

Thx but I would think trapped air would work its way out eventually

[JSeery]

Originally Posted by 30-9

Thx but I would think trapped air would work its way out eventually

What thermostat are you using that doesn't allow the temp to get to 160? For starters I would want at least a 180 degree thermostat and if you are having problems keeping the temperature up block off part of the radiator with some cardboard. Running the engine below 160 is not good on the engine in addition to not producing hot air. The engine will not lubricate well at low temperatures and you end up with increased wear. In addition the oil will not get hot enough to burn of the impurities and you will end up with a lot of sludge build up. Need to get the operating temperature up!

[blucar]

Originally Posted by 30-9

I kinda agree with jseery. I think it should work either way, but it's not.

My valve is open, I had the heater out last year and flushed it out. So cold up here temp gauge never hits 160 in winter months. I get (At best) luke warm air, nothing that will warm cabin.

I'm open to suggestions.

For a heater to work in the winter months the engine should have a 180 thermostat.
Many people have the bad habit of thinking that a 160 degree is better for their engine..
I can clearly recall the automotive class I attended in 1952 that covered automotive cooling systems. The class stressed the importance of 180 degree's being the optimum temp for an engine. At 180 the majority of the contaminates formed in the oil during the combustion process, would be burned/cooked out of the oil, thereby extending engine life.
The automotive standard is now 195... I know several people that insist on running 160 thermostats in their late model engines, then they wonder why the engine runs poorly.
I recently installed a '97 Chevy 5.7 Vortec engine and 4L60 AT in my '64 C10 pickup.
We used the stock ECM (computer) that was reprogrammed for my application. The mechanic assisting me with the installation wanted to use a 160 stat, I insisted on a 195 because that is what the "book" called for..

[30-9]

Js I don't know what thermostats I have in there, bought car and never opened it up.

As always you provided me very good advise and I will try it

[JSeery]

Originally Posted by 30-9

Js I don't know what thermostats I have in there, bought car and never opened it up.

As always you provided me very good advise and I will try it

For now you can just block off part of the radiator to get the temperature up. It is a trial and error process to find the correct amount to block off.

[JSeery]

Originally Posted by blucar

For a heater to work in the winter months the engine should have a 180 thermostat.
Many people have the bad habit of thinking that a 160 degree is better for their engine..
I can clearly recall the automotive class I attended in 1952 that covered automotive cooling systems. The class stressed the importance of 180 degree's being the optimum temp for an engine. At 180 the majority of the contaminates formed in the oil during the combustion process, would be burned/cooked out of the oil, thereby extending engine life.
The automotive standard is now 195... I know several people that insist on running 160 thermostats in their late model engines, then they wonder why the engine runs poorly.
I recently installed a '97 Chevy 5.7 Vortec engine and 4L60 AT in my '64 C10 pickup.
We used the stock ECM (computer) that was reprogrammed for my application. The mechanic assisting me with the installation wanted to use a 160 stat, I insisted on a 195 because that is what the "book" called for..

So true, there are a lot of flathead folks that believe in the low temperature approach. The hotter an engine runs the better (within reason and other constraints). Engine efficiency is dependent (along with other factors) on engine temperature.

[Kube]

Originally Posted by 30-9

Thx but I would think trapped air would work its way out eventually

Not necessarily.

[30-9]

Can I purchase the 180'thermo at Napa? Anyone have part number?

[V8 Bob]

Originally Posted by JM 35 Sedan

...............
Now, on the other hand, some folks here post pictures sooooo damn LARGE that they will not fit on the screen of my tablet, and are an even worse fit on my Droid (largest sceen available) smart phone. Sometimes these attached pictures are so large that I have to download them, and then downsize them, to be able view them properly. Not gonna mention any names here

Sorry 'bout that. They appear pretty normal sized on my desk top screen. BUT, at least you can see the detail VERY well. ....

[Kube]

Once the engine is up to operating temperature check the temperature of each heater hose at about 3" from the firewall. They should be very close in temperature. If not, I'd be looking at getting the core flushed professionally.

[Kube]

Originally Posted by 30-9

Can I purchase the 180'thermo at Napa? Anyone have part number?

Yes, but they will not fit properly and may very well "ride up" in to the radiator hoses w/o modifying.

[30-9]

Thanks Kube will look online - carpenters/c&g/drake

[JSeery]

Originally Posted by 30-9

Can I purchase the 180'thermo at Napa? Anyone have part number?

Henry has a method of using newer style thermostats with some small wires to retain them. I have not tried that method. He has posted on it several times.

http://fordbarn.com/forum/showthread...rmostat&page=2

Post #28 has a photo of what he does.

[30-9]

American inginuity Pretty cool

Back to needing Napa part number

[37 Coupe]

One thing I never understood about the difficulty of finding correct thermostats at Napa or other parts stores.What is wrong with buying the ones made back in the day that worked? If you are not in a hurry or plan ahead these are on Ebay almost all of the time,NOS or NOSR in the box made in the USA. Shouldn't they fit without all the hassle of the new China ones? This is what I have used when I do use thermostats. Search for Ford Flathead thermostats on Ebay but have seen also all the time at car parts auctions I frequent.

[JSeery]

No a good idea in this case. They are no longer used for a reason. They have a bad failure mod!

There are other thermostats available. You can also use a sleeve to retain them.

[petehoovie]

This is the hook-up in my '37....

[Kube]

Originally Posted by 30-9

Thanks Kube will look online - carpenters/c&g/drake

They (correct fitting) are not available as new replacements. You can use the new ones with a fairly simple modification. JSeery posted a link that shows how to do it.
Or, as I prefer to do - buy NOS or NORS. they are readily available.

[37 Coupe]

Originally Posted by JSeery

No a good idea in this case. They are no longer used for a reason. They have a bad failure mod!

There are other thermostats available. You can also use a sleeve to retain them.

A bad failure mod?

[JSeery]

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I don't remember the details on them at the moment and I'm painting. I will have to do a search on it and post later.

[37 Coupe]

I have had NOS Genuine Ford ones fail shut but I had one do the same on a new Jeep I had. I just figured they (NOS)would still be better than China ones. If a new one is out there that fails open and fits a 59AB I am interested.

[Kube]

Wow! What a diverse number of opinions on the original post in regard to how to properly attach the heater hoses.
Per Ford's instructions, 1939 - 1940 FORD hot water heater: The lower nipple of the heater core connects to to the valve on the cylinder head.
A little actual research goes a long way...

[Kube]

Originally Posted by big job

Old golden rule; bottom to top or top to bottom, which means bottom is water pump
that goes to top of heater and bottom of heater goes the top (head) ....

Bingo! We have a winner! Great and ACCURATE advice...

[37 Coupe]

I thought I explained pretty good on post #24 a week or so ago.

[petehoovie]

Originally Posted by 37 Coupe

I thought I explained pretty good on post #24 a week or so ago.

Yes, you did....

[Kube]

Originally Posted by 37 Coupe

I thought I explained pretty good on post #24 a week or so ago.

You did and in fact were one of the few that did and did so correctly. I only brought this back up as I was asked to.