Radiator fluid question
 

I'm fairly new to the model A world and I have a question that has probably been answered many times before.

I recently bought a '31 coupe and I've been doing routine maintenace on it. I'm getting ready to drain the radiator and I was looking for guidence on what I should put back into it. Straight water or a mix of water and antifreeze? How many total gallons of fluid go back into the radiator?

I live in MN so yes the cold winter weather is approaching. I don't know what's in it now and I want to make sure I drain it incase it's straight water. I don't want the block to crack during the winter.

Advice on this is greatly appreciated.

Thanks!

Re: Radiator fluid question
 

50-50 mix with distilled water and antifreeze

Re: Radiator fluid question
 

i use straight pre-mixed antifreeze.

Re: Radiator fluid question
 

I use 50/50 distilled water and antifreeze. Also I'm in Texas not real cold here. Bill

Re: Radiator fluid question
 

Use a 50/50 blend from the auto parts in my 31 coupe. Takes 2 gallons and just a bit of water to bring the lever up just over the baffle.

Re: Radiator fluid question
 

I do the same as Mike 50/50 distilled water adn Prestone.

Re: Radiator fluid question
 

...which leads me to the next question:
Why to use distilled water with the antifreeze

Re: Radiator fluid question
 

ever cleaned a swamp cooler after it has been used all summer? notice all the crude in the bottom and on the pads? they are there because of all the minerals in the water, if you use regular water in a location that has hard water your radiator and the inside of your engine will look like that, heat causes the minerals to attach them selfs to the rad core and water passages in your engine, check the back of the anti freeze bottle, it will tell you how much anti freeze to use per gallon of water to protect rad to what ever temp you may incur in your area

Re: Radiator fluid question
 

Thanks everyone for your help.

Also how can you tell how much fluid you have in the radiator? I know with my '51 I can remove the cap and see the level of the fluid but with the '31 you can't see down into the radiator. I'm guessing if I drain it all out and replace with 50/50 I would be putting in 2-3 gallons? According to the Les Andrews book it says 3 gallons.

Re: Radiator fluid question
 

Probably a little more than two gallons, I find that they seek their own fluid level mine is just over the core any more just leaves the radiator, runs cool all the time....

Re: Radiator fluid question
 

Thanks for answer.
i guess i need a new radiator anyway.
Tried to clean mine as stated somwhere else by Tom Wesenberg.
Water is clean an not greasy anymore, but radiator seems to be barred somewhere.
difference between Top and Bottom of radiator is about 10 degrees
and it likes to go hot.
Will have to take it out to do this "4-second-drain-test"
Best regards Christoph

Re: Radiator fluid question
 

The drain test is meaningless. Before buying a new radiator I'd remove the top or bottom tank and try rodding out the tubes. You can buy a very long thin drill bit. I would try spinning that by hand to remove any crud in the tubes. Then if it goes all the way through follow up with a .22 calibre rifle cleaning brush. This is for the 1928-9 round tube radiators. For the flat tube radiators you'd need a long thin blade, like a transmission dipstick.

Have you asked at any radiator shops how much it would cost to rod it out?

I removed the tanks from my 1950 Studebaker radiator years ago to do some repairs. You have to use a small pointed flame and heat the solder on the tank seam, then quickly blow away the molten solder with compressed air and a blow gun. Do about a half inch at a time and keep working around the tank until all the solder is blown away. Then you should be able to lightly pry the tank away. Once the tank is off check the solder around the tubes to make sure you didn't melt any of it away.

Also, I've heard good results using vinegar to clean the deposits out. I haven't tried that yet, but it's worth a try before spending big bucks on a new radiator.

Re: Radiator fluid question
 

Where you are, 50 - 50 water and antifreeze.

Re: Radiator fluid question
 

Have you used a temperature gun to shoot several spots on the radiator to find cold spots? Spots with a lower temp than the tubes either side of it (but at the same height) would indicate blockage.

My radiator wasn't indicating blockage but it only showed about a 20 degree drop from the top tank to the bottom tank and the temp across the middle was about 10* lower than the top tank. Using a 160* thermostat, my top tank was running about 215* before cleaning the radiator. After the cleaning with heavy duty floor degreaser and then again using washing soda the operating temp of the engine has dropped by at least 20*. I will have to shoot the radiator again on a hot day to see what the temp drop is from the top tank to the bottom tank, but I seem to recall about 40* and I'm using a 160* thermostat.

Re: Radiator fluid question
 

Thank you Tom .
Allways a pleasure to read your comments.
Im sadly in lack of the necessary "McGuyver-Gen"
and im allways to fast in spending the bucks...
I tried a "radiator-cleaner" (whatever this is)
I tried vinegar-type-cleaner with no effect
Then i read your Threat (somewhere some weeks ago)
and used degreaser which took the grease away and
brought a fresh smell :D
Had to rinse about 10 times untill taste changed
to "normal water". I got a temperature-Gun but from
my point of view the difference in temps (Top-to-Bottom)
wasnt as high as expected and some dry-crusty-dirt is still
visible (Water stays clean even driving all day.....)
I didnt have the idea to look for cold spots with the gun.
Thank you again.
Will try even daytime-temps now are low over here.
For sure i will try a radiator shop too as my radiator looks great.
(Due to transportation and taxes, prices for US-Model-"A"-parts
are more than duplicated till i hold them over here ).
Best Regards Christoph