So I'm now ready to make my custom overflow tank for my '31. I suppose the radiator isn't perfect and it sometimes heats up enough to spit out some antifreeze if I run up a long grade.

I know I should mount the tank as high as possible. Should I mount it with the hose as far down the tank as I can or up a small amount?

Should I leave breathing holes at the top or will it be OK to have it sealed off?

Thanks,
Brandon

I used an overflow tank from a street rod. The vent tubes inside the tank are two diffent heights, the top of the radiator (overflow) attaches to the short tube so the tank fills. The overflow attaches to the longer tube so the overflow can be discharged.
I mounted the tank on the radiator brackets. It's worked fine.
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Hey Karl, thanks for the reply. I remember you posting your picture before and I really like the look of what you've got there. I'm having a bit of trouble visualizing what you mean there and I can't quite make out in the picture well enough to see.
I'm either going to use a mason jar or an old, large coke bottle just because I think it might be kinda neat. In this case, how would I go about setting that up? Would I do more than simply running the overflow line into the bottom of the tank?

Thanks,
Brandon

You'll need two tubes in the jar-one at the bottom to take the radiator overflow which will fill the jar and one set close to the top to blow off the excess as the jar fills.
Sounds like a cool project.

The hose from the radiator overflow tube can be all the way to the bottom but it will slow the flow and also suck any solids back into the radiator. A small gap between the hose and coke bottle bottom has advantages. If too much gap you lose capacity to accept coolant as it will only suck in fluid to the bottom of the hose.

Sorry, it's hard for me to visualize things with just words. Assuming I went with a mason jar, is this pretty much what I would need according to what everyone has said.

The overflow from the radiator goes in near the bottom of the jar, but not all the way at the bottom to allow sediment to be trapped at the very bottom. I can then remove and clean out the sediment from time to time.

The lid of the jar would have another hose in it that would act as the original overflow line did, exiting under the car.



Thanks,
Brandon

Brandon,
That would work but actually all you have to do is put the hose from the overflow tube down through the top and extending nearly to the bottom of the container. The advantage with a one liter Coke or Pepsi bottle is that the hose can go down through the top, extend nearly to the bottom and it fits close enough that there is space for air to escape and and enter past the hose but minimize splashing any liquid out.

So I'm guessing that with it being non pressurized it would be necessary to pour the contents of the jug back into the radiator if it fills up?

Brandon

Hi Brandon,

To fit an overflow recovery tank on my 28 I put a rubber washer from the Filling Station on the radiator cap. This seals the system, with very low pressure, and any overflow is drawn back into the radiator when it cools. My tank is mounted down near the sump, works fine.

Please see the link to a posting I put on my blog rearding fitting an overflow tank.

http://my28chev.blogspot.com.au/2011/09/improvement-no-6-done-in-80s-radiator.html

Regards

Ray

Vetteman61
I think that with the radiator cap on and sealed at the top when the radiator pushes out the water it would go to the over flow tank then when the radiator cools it will suck the water out of the overflow tank back into the radiator through the same hose

Hi Vetteman61,

You are 100% corect. The water level in the overflow tank on a cold engine just needs to cover the inlet tube.

Regards

Ray