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Cooling System Questions - 1948 Thermodyne.

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Here are my rookie questions:

I am about to backflush the radiator and block on my 1948 firie truck. It appears to have been long ago when last serviced.

Are there 1 or 2 thermostats located in the housing between radiator and block?

Is there a retail source for compatible thermostats?

Is there a retail source for compatible radiator caps?

And finally, what is the 1/8" metal line conencting the thermosatat housing to what I am guessing is the water pump?

All help appreciated. I have a million more rookie questions.

Donny

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Here are my rookie questions:

I am about to backflush the radiator and block on my 1948 firie truck. It appears to have been long ago when last serviced.

Are there 1 or 2 thermostats located in the housing between radiator and block?

Is there a retail source for compatible thermostats?

Is there a retail source for compatible radiator caps?

And finally, what is the 1/8" metal line conencting the thermosatat housing to what I am guessing is the water pump?

All help appreciated. I have a million more rookie questions.

Donny

Donny,

Try NAPA and see if they can match up the cap and thermostat, I do not know if there are one or two but my guess is there is only one.

I do not know what the line from the water pump is for, my first guess is that it may be for the aux. cooling that helps keep the engine cool on extended pumping but, that is supposed to be a closed sysytem and does not mix with the cooling water. The water pump on my truck did not have one but had a plug in place, when I replaced the pump the seconed one had the line but it was crimped and I replaced the fitting with a new plug. The replacment pump did not come from an fire engine, it came off and L series road tractor so whatever it is for is not fire engine related, I will look at my manuals and books tonight and see what I can find out for you.

David

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Donny,

Try NAPA and see if they can match up the cap and thermostat, I do not know if there are one or two but my guess is there is only one.

I do not know what the line from the water pump is for, my first guess is that it may be for the aux. cooling that helps keep the engine cool on extended pumping but, that is supposed to be a closed sysytem and does not mix with the cooling water. The water pump on my truck did not have one but had a plug in place, when I replaced the pump the seconed one had the line but it was crimped and I replaced the fitting with a new plug. The replacment pump did not come from an fire engine, it came off and L series road tractor so whatever it is for is not fire engine related, I will look at my manuals and books tonight and see what I can find out for you.

David

I plan to spend all day tomarrow on the truck. I appreciate your help.

Donny

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I plan to spend all day tomarrow on the truck. I appreciate your help.

Donny

The ENF510A has only one thermostat according to my manual, I still do not know where the line goes from the water pump, I have one more book to check. My wife cleaned up my desk so I have to track it down, as soon as I find it I will get back to you, it has some very good detailed drawings of the Mack engines.

Enjoy your day working on your truck!

David

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Check to see if the small line your looking at is a "Radiator Refill" line, I have seen alot of older fire trucks with this option. It was used to refill the cooling system without shutting down the truck during a pumping operation when a engine over heat occured. there should be a valve on your pump panel marked for this purpose if it's got one. Good Luck, E.S.D. :thumb:

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Check to see if the small line your looking at is a "Radiator Refill" line, I have seen alot of older fire trucks with this option. It was used to refill the cooling system without shutting down the truck during a pumping operation when a engine over heat occured. there should be a valve on your pump panel marked for this purpose if it's got one. Good Luck, E.S.D. :thumb:

Thanks for the info. The ID of the line is only 1/16 to 1/32 and is direct connect between thermostat housing and water pump with no inline valve or control.

David (Dwaits) has the same line but it is removed and bull plugged at both ends.

Thanks.

Donny

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on my '47 LS-85 with a 707 that 1/8 inch line from the water pump to the thermostat housing is called a water pump to water manifold bleeder. j.j. :thumb:

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on my '47 LS-85 with a 707 that 1/8 inch line from the water pump to the thermostat housing is called a water pump to water manifold bleeder. j.j. :thumb:

Donny,

I think I may have told you wrong on where the line goes.

If it is what twostick described above I do have that line on my engine but it is rubber, on down the radiator line coming out of the pump is what I thought you were asking about and it is what I described to you as being plugged.

I will take a picture of it when I get back home after work.

David

Is this the line you are asking about? If then it is what Twostick told you.

post-86-1158104908_thumb.jpg

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JJ and David,

Thanks for the help. I have been away not near a computer. My line is metal not rubber. Surely it must be plugged. What is its purpose? Your pic is correct.

Do your motors have twin coils/distributors?

Donny

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JJ and David,

Thanks for the help. I have been away not near a computer. My line is metal not rubber. Surely it must be plugged. What is its purpose? Your pic is correct.

Do your motors have twin coils/distributors?

Donny

I am not exactly sure what it does but it is some sort of pressure relief line, I am thinking for when the system is shut of from the radiator maybe.

Yes mine does have two coils and distributors.

I saw your post on burning up the points and coils, go over to the ATHS board at aths.org and log on to the disscusion page, there are lots of guys on that board that can give you faster answers to some of your questions.

This forum (BMT) has a great bunch of guys on it but for questions about trucks and engines as old as ours the guys at ATHS are better at answering questions about the older engines.

David

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