# Radiator overflow tank



## Nicholas (Jan 16, 2017)

Hi everyone. I was wondering about installing a radiator overflow tank on my '71 GTO. My engine doesn't puke out antifreeze anymore. I think it found it's own comfortable level which when cold, is about 1-1.5 inches down from the top. This empty space represents maybe room for another quart or so of liquid. I'm wondering how important this empty space is to the cooling potential?? Does it really matter that much?? If I fill it cold, wouldn't this tank capture the overflow and then get reintroduced to the radiator when need be?? Any harm in doing that?? Or maybe if it's not broken, don't fix it?? Any thoughts on this?? Thanks, Nicholas.


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## PontiacJim (Dec 29, 2012)

Nicholas said:


> Hi everyone. I was wondering about installing a radiator overflow tank on my '71 GTO. My engine doesn't puke out antifreeze anymore. I think it found it's own comfortable level which when cold, is about 1-1.5 inches down from the top. This empty space represents maybe room for another quart or so of liquid. I'm wondering how important this empty space is to the cooling potential?? Does it really matter that much?? If I fill it cold, wouldn't this tank capture the overflow and then get reintroduced to the radiator when need be?? Any harm in doing that?? Or maybe if it's not broken, don't fix it?? Any thoughts on this?? Thanks, Nicholas.


Why add it? You fill the radiator to max. The engine heats up and pushes the expanded coolant out. The engine now operates on the coolant left in the radiator/cooling system, minus the coolant pushed into the overflow tank. So how does the coolant in the overflow tank sitting idle next to the radiator help cool the engine - it isn't in the radiator to help cooling?

The engine cools, coolant contracts and draws the 1/2 quart of coolant back into the radiator. What did you gain other than a constant cycle of excess coolant that wont be used pushed into an overflow tank so it can be sucked back up into a cool radiator that is cool because the engine is no longer running?

The radiator and coolant are designed to cool the engine as is from the factory. If it is not, then you have an issue that needs to be looked into.

Yes, "if it ain't broke, then don't fix it." :yesnod:


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## Lemans guy (Oct 14, 2014)

I agree with PJ,.....I don’t use an overflow tank. But some guys do, on these cars it is like chicken soup when you are sick, won’t hurt....

But may not do much either. Newer cars run different systems, they have the overflow tank operating under pressure, you fill thru that pressure cap. On our cars the pressure cap is the radiator cap, it has a spring and a certain pressure like 16 PSI.

When the pressure releases, if the coolant is too much it flows into the whiskey bottle that you see on rat rods at the car show. The whisky bottle is not under pressure, it is just a bottle for overflow,.....


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## Nicholas (Jan 16, 2017)

Thanks for the advice guys. There will be no tank. I like to tinker too much, that's my problem, Nicholas.


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## PontiacJim (Dec 29, 2012)

Nicholas said:


> Thanks for the advice guys. There will be no tank. I like to tinker too much, that's my problem, Nicholas.


We all do. LOL


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