Yes! A very little bit of water makes a great deal of steam!!

John

On 9/9/2013 4:42 PM, Jim Felder wrote:
> Yes, but only after it had displaced a great deal of coolant.
>
> Jim
>
>
> On Mon, Sep 9, 2013 at 4:18 PM, Tom Carchrae <tom@carchrae.net> wrote:
>
>> Great explanation Mark.  Thank you.
>>
>> If the "air" is indeed steam, then wouldn't it return to liquid form once
>> the system cools?
>>
>>
>>
>>
>>
>> On Mon, Sep 9, 2013 at 1:59 PM, mark drillock <mdrillock@cox.net> wrote:
>>
>>> There are 2 major choices for the "air" that appears to force the coolant
>>> out into the overflow tank in your case. Either you have a hot spot that
>> is
>>> boiling the coolant and making steam, or you have some failure that is
>>> letting high pressure combustion gases seep into the cooling system and
>>> displacing the coolant. A third variation would be if you were foolishly
>>> running straight water then steam is going to happen much more easily.
>> The
>>> coolant 50/50 mix doesn't boil until it is about 50 degrees hotter than
>>> straight water does. If the cap is bad and you are running straight water
>>> then that is a double whammy since a pressurized system raises the
>> boiling
>>> point. A leaking cap valve reduces the system pressure so boiling is more
>>> likely to occur with a bad cap.
>>>
>>> Whether the "air" is combustion gases or steam, its source location is
>>> away from the coolant tank. So when it first appears in the system it
>> adds
>>> rapid pressure to the system that will want to escape somehow. Typically
>>> the pressure will escape through the overflow nipple of the cap and into
>>> the overflow tank, pushing liquid out since that is what is in the tank
>> at
>>> that moment. The "air" will later end up gathered at the main tank. If it
>>> had originated at the main tank it would be the first thing forced out
>> the
>>> cap nipple but that is not the case. Thus the source is elsewhere.
>>>
>>> Mark
>>>
>>>
>>> Tom Carchrae wrote:
>>>
>>>> This is not a different issue - this is my cooling issue....  :)
>>>>
>>>> I have a question to ask the experts regarding the bad cap theory.  I
>> get
>>>> how the fluid ends up in the overflow tank - but if it just a cap, where
>>>> does the air/gas come from the displaces the coolant - and why does it
>> not
>>>> pull the coolant back into the pressure tank when it cools?
>>>>
>>>>
>>>>
>>
>