Why Does A Coolant System Pressurising Stop It Overheating?

[kyepan 291]

Simple question.. or silly question..

 

or is it just that the system can run at over 100 deg and pressurise.. instead of getting to 100 and boiling.

 

cheers

 

J

[Tom Fenton 1,548]

Increase working pressure and you increase the boiling point, run a cooling system with no pressure cap and it will boil sooner, that then causes it to spew water out, which reduces coolant capacity, then you have a vicious circle.

[Baz 421]

Charles's Law.

[Slo 283 1 Cars]

With a 205 its sods law and usually when your skint

[welshpug 1,666]

http://www.engineeri...ater-d_926.html

 

look at the second graph, 1 bar is normal air pressure, so the usual 100 degrees C, next line across is 2 bar, which is the usual expansion tank cap release pressure inclusive of normal atmosphere pressure, so 1 bar system pressure, the temperature is circa 120c, the TD and most later pugs run at 1.4 bar which would be around 130 c.

 

bit more on Wiki

 

https://en.wikipedia...i/Boiling_point

Edited October 10, 2012 by welshpug

[dcc 855]

Take note that water in an engine is also NOT pure H2O.

[welshpug 1,666]

Take note that water in an engine is also NOT pure H2O.

 

or rather, SHOULD NOT be pure H²O

[BERTMAN 40 1 Cars]

H₂O* to be pedantic

[grandos 16]

Being pedantic it should also say 'overheating' in the title and not 'overhearting' like some love sick puppy!

[cheesegrater 43 1 Cars]

Same reason as why water boils at a lower temp at altitude!