Coolant tank keeps puking coolant

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Blackbeard44

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All the squares I have owned over the years always liked to be inch or so low in the radiator when I would check them cold.

when you open the cap on a cold motor is there any pressure?
 

Blackbeard44

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here is a test I would do before I started thinkin about a cracked head.

open the cap on a cold motor just in case there is some pressure to release it. re-install it

squeeze the upper rad hose to establish how solid it is.

start the motor and hurry back to the radiator, start squeezing the upper hose and see if it becomes solid before the motor heats up.

if a cracked cylinder head is the problem the upper hose should become very hard to squeeze very fast, like 30 seconds fast
 

Ricko1966

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Ok one more time,take off the radiator cap tape a plastic bag around the filler spout. Start the truck. Does the plastic bag blow up? Something is displacing the water.My money says it's combustion gasses.The overflow tank is not even existent on older cars and they don't go around puking out gallons of antifreeze. Heat causes expansion, expansion causes pressure which the cap holds in until cap pressure is exceeded.I'll bet it will blow up a plastic bag.
 
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Rusty Nail

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One way to find out!
It be bad juju if you haz exhaust gas in the cooling system..:nono:

Why the hell would I take a test?
 

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Did some testing.....

First addressing a cracked head as suggested. I started it cold, run under the hood and felt the rad hose. Soft, wasn’t hard at all.

Next the bag trick. I cupped a plastic bag over the rad and it didn’t do anything. I let it idle a bit and still nothing, it didn’t inflate at all.

Let it idle with the cap off, no bubbles.

I ended up buying a radiator combustion gas tester at O’Reilly’s tonight and tested the system twice. There were no combustion gasses present in the system. Fluid never turned yellow.
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Tested the radiator cap, it failed. I bought a new one and will see what happens...
 
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Blackbeard44

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Thats good news, no hydro carbons in the radiator and bad radiator cap is best case senario in my book, hopefully all that you needed was a new cap
 

bucket

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Not trying to be rude here, but I think you are severely overestimating the amount of coolant that has spilled on the ground.

It sounds to me like the overflow tank has a small crack in it, like many do, and when the fluid level rises with temperature, it leaks some out. Then you top it off later, and it does the same thing again.

Just let it keep leaking without topping it off and see how low it gets. My guess is it will end up with no contents in the bottle and the radiator will stay full or close to full, and it will no longer puke on the ground. If you have the tall radiator, the coolant level can be several inches from the top and it will still cool well, so you don't need to worry about it getting excessively low and hurting anything right away.
 

bucket

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Nevermind, I see you have the short radiator. But even with the short one, 1-2" down will still cool the truck properly.
 

79dentside

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So far so good. I replaced the thermostat with a 180 degree instead of the 160. I let it idle for 50 minutes with some throttle wraps, no issues. Drove it today, no issues. In fact, the overflow tank finally dropped after sucking the coolant back in after loosing it. even after loosing coolant before, the resivoir was always full and never got sucked back into the radiator. Now it has.

Thanks guys!
 

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I had the exact same problem not too long ago. I changed my radiator cap out, thermostat, checked all my hoses, etc.
Never saw any blow back, or any coolant in the oil pan or heads.
Finally I saw my weep hole was barely leaking from the water pump. I never could tell cause of the engine bay was covered in coolant.
I changed out the water pump and problem went away.

I had a valve job done before the problem occurred. So I some what knew the heads should be in good condition, but could have been a head gasket leak. New water pump fixed my issue though.
 

79dentside

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Th
I had the exact same problem not too long ago. I changed my radiator cap out, thermostat, checked all my hoses, etc.
Never saw any blow back, or any coolant in the oil pan or heads.
Finally I saw my weep hole was barely leaking from the water pump. I never could tell cause of the engine bay was covered in coolant.
I changed out the water pump and problem went away.

I had a valve job done before the problem occurred. So I some what knew the heads should be in good condition, but could have been a head gasket leak. New water pump fixed my issue though.
That’s awesome!!
 

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