1957 burps fluid out

[farmerdick]

1957 with 312 does not over heat but burps out about 8oz of fluid after engine is shut down(about an hour or two later). changed thermostat and even added some Water Wetter. Any ideas?
Thanks
Richard

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[ICON 56]

Could be a heater core issue.When was the last time you changed the antifreeze?

 

[Ward 57]

You could be overfilling it. The water level should be just over the baffle you can see. The top half is the expansion tank and needs room for the expanded hot water. Too much coolant and it will just burp it out, usually while running but the heat soak from a hot engine after shutdown will do it also.

 

[zeroroadkill]

Yup don’t fill it all the way up! 50’s cars didn’t have a expansion tank, the radiator tank was the expansion tank and if you fill it to the top it will puke! Been there done that ?

 

[farmerdick]

The water level is just below the 1" hole in the bottom of the expansion tank. It has always been that way since i got the car last fall. I have never added anymore fluid than what it already had. You would have thought
it would have reached its happy level after three times. I can see the water level to be about 1/4" below the hole in the bottom of the expansion tank as of today. ``````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````

 

[Ward 57]

I can't member If it was here or another car board, but the poster mentioned that with his car that was the system's happy place. Mine likes it with the baffle covered.
You also might check the radiator cap and seals. The ones I see in the catalogs have 13psi caps which I believe is standard.
If it doesn't overheat you may not have a problem.

 

[Tom Alpers]

1957 with 312 does not over heat but burps out about 8oz of fluid after engine is shut down(about an hour or two later). changed thermostat and even added some Water Wetter. Any ideas?
Thanks
Richard

 

[Selfrich]

You might want a higher pressure radiator cap. 13 psi may be to low.

A radiator cap keeps the cooling system pressured which raises the boiling point. For every pound of pressure in a closed cooling system you raise the boiling point by three degrees. At sea level, water boils at 212 degrees. By adding 16 pounds of pressure to the system you will raise the boiling point to 260 degrees.

My radiator cap keep over flowing also. I increased the pressure on the cap and solved the problem. You might create problems also if the system won't support the added pressure. Is the radiator able to support the pressure? Is the antifreeze new?

 

[rapidrobert]

Have the cap and the cooling system pressure tested. A weak cap can cause this. Exhaust gases in the system will definitely cause this. Now for the science, as Selfrich mentioned the pressurized system boils at a higher point. Your car should have a 13lb. cap so theoretically the coolant should start to boil at 230 degrees and when it boils it creates pressure. When you shut your car off the coolant quits circulating and superheats to a certain extent. If it goes above 230 degrees, the cap lets the excess pressure off along with some coolant. Being too full can increase this. Letting the car idle for a minute or so before shutting off can help but isn't always a cure. This is why vehicles from the last few decades have overflow reservoirs. Now worst-case scenario is exhaust gases causing this, such as cracked head or a leaking head gasket. Sorry for the long reply but this explains it.

 

[zeroroadkill]

With Rapidrobert’s reply, check your oil for water (chocolate milk color) would indicate a blown intake or head gasket ???

 

[Phufe]

1957 with 312 does not over heat but burps out about 8oz of fluid after engine is shut down(about an hour or two later). changed thermostat and even added some Water Wetter. Any ideas?
Thanks
Richard

You are probably over filling the radiator. When I fill mine, I always joke that mine needs a diaper because it pees itself. When the car gets hot, it builds up pressure and will push the pressure cap up and the water will escape through the overflow. Fill it, let it burp out what it doesn't want, and it will stop. Try not to fill the radiator to the brim. Leave a little room. As long as it isn't overheating, you are good.