Boiling radiator

[H munster]

Quick question guys, I got a 94 EX 4.0 A4LD that sounds like the radiator is boiling when I shut it off. I did a search and everyony says when theirs did this it also overheated. Mine doesnt run hot at all even when ambient was over 100 a couple days ago. How can it boil if the engine doesnt overheat?

 

[AllanD]

Residual heat in the engine block will creat boiling water in the cooling system after the engine is shut off because coolant is not being circulated... the water pump is no longer turning.

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[Wicked_Sludge]

have your radiator cap pressure checked. a weak cap will fail to hold system pressure, which can allow the coolant to boil with little or no overheating problems.

 

[shadetree]

have your radiator cap pressure checked. a weak cap will fail to hold system pressure, which can allow the coolant to boil with little or no overheating problems.

Ditto. Its called "percolation." Also, be careful of the replacement cap. I went thru that on one of my Merks. I had a new Stant cap, and went thru hell(long story) trying to determine what was wrong with the damn thing. Come to find out Stant had the wrong part number on the cap. shady

 

[Wicked_Sludge]

percolation, eh....i guess you could leave the cap and use it to make some coffee

 

[shadetree]

percolation, eh....i guess you could leave the cap and use it to make some coffee

Yep. Just throw in some coffee grounds, and let it fill the overflow bottle. Hell, it might be pretty good, who knows. I've tasted some nasty shit in my time. shady

 

[Jorley]

Ditto. Its called "percolation." Also, be careful of the replacement cap. I went thru that on one of my Merks. I had a new Stant cap, and went thru hell(long story) trying to determine what was wrong with the damn thing. Come to find out Stant had the wrong part number on the cap. shady

I don't percolation is quite the right word. To percolate means to filter. As when installing a drainage system you have to do a precolation test to determine the soil's ability to absorb the water. Or, as in coffee, the water filtering thru the coffee grounds

Source:
http://dictionary.reference.com/search?q=percolation

 

[shadetree]

I don't percolation is quite the right word. To percolate means to filter. As when installing a drainage system you have to do a precolation test to determine the soil's ability to absorb the water. Or, as in coffee, the water filtering thru the coffee grounds

Source:
http://dictionary.reference.com/search?q=percolation

It is percolation. The same process as the coffee pot sans coffee and filter. That has nothing to do with it. It is the heating and movement of the water. shady

 

[Jorley]

I'm not wanting to start an arguement, I'm just going by the definition of the word,but wouldn't coffee pot, sans coffee and filter, be boiling?

 

[MAKG]

Percolation is movement of fluid through a solid porous medium. Filter, aquifer, whatever. It does not not need to be boiling. Groundwater percolates.

The technical term for what is being described here is "heat soak." When the engine is running, cylinders are always hotter than the water jacket because combustion is occurring inside. Stop the engine, and they equalize (meaning, cylinder cools down, water jacket heats up). This can cause localized boiling, especially if the radiator cap is a bit weak or if there are air pockets on top of the heads.

 

[shadetree]

Damn!!! As Dave R. would say, "picking nits." Whatever the correct technical definition of the word, the radiator guys call it percolation when the engine is shut off and the water boils out the overflow. I know it has several applications, don't really care. shady

I'm not wanting to start an arguement, I'm just going by the definition of the word,but wouldn't coffee pot, sans coffee and filter, be boiling?

Which definition? It has about a thousand depending on which application is being discussed. shady