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Originally Posted by kilosierra
The first time might be right, but isn`t the coolant system pressurized and that because the boiling point independent from the altitude?
No expert here, just guessing.
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I'm no airplane engine expert, but I do know plenty about automotive engines. The reason the coolant system is pressurized is because it raises the boiling point almost 50 degrees F (212 + 50 in F). And that should be completely separate from atmospheric pressure, as the cap, overflow system, and t-stat(s) all play an important role in maintaining that coolant equilibrium.
Quote:
Originally Posted by speculum jockey
If it wasn't pressurized then it would leak all over the place. Anything that contains a liquid or gas that is not meant to escape will be pressurized. Balloons, cans of soda, your air mattress. All pressurized.
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No. It's pressurized to raise the boiling point of the coolant. It has nothing to do with keeping it from leaking. Once cap pressure is overcame, it will siphon (leak) right on by the radiator until it can be sucked back in. You could take a huge radiator, without a cap, and leave the level of coolant lower and the system will never leak (no pressure), but it won't be as efficient.
Quote:
Originally Posted by Catseye
I thought coolant was in a closed looped system under pressure and atmospheric pressure would not have any affect?
Interesting if it does.
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I'd have to agree with you. I don't see how it could be effected, but I don't know.
@All - I don't know how much better cooling you'll get with high altitude conditions. Obviously it will help, but remember the coolant is there to keep the internal engine (where combustion occurs - a temperature that only slightly varies (lean/rich) in the combustion chamber) Outside air helps to cool the coolant obviously, through radiators, but that cold outside air also makes the engine need less fuel at altitude (less air density/less volume of oxygen) and colder air + less fuel = hotter combustion temps which = warmer base engine to cool.
Again, I have no idea how much the efficiency of cooling is higher altitude (super cold air) on a tiny radiator, but so much else is reliant upon the water pump and combustion chamber temp as well.
Would be neat if someone could find an article on it!