John Everything you say makes perfect sense apart from your assertion that antifreeze elevates the boiling point. Have I got this totally wrong? Anti-freeze is mainly ethanol based (think Italian wine scandals!!!!!!) It boils at a lower temp than water. Therefore an ethanol/water mixture will boil at a lower temperature (assuming identical pressure/temperature) than a pure water solution.......... Obviously the lower boiling point is more than counteracted by the fact that the system is under pressure, but adding ethanol to water will surely lower both the boiling & freezing points of the solution?????
--- On Tue, 14/4/09, John M. Steele <[email protected]> wrote: From: John M. Steele <[email protected]> Subject: [USMA:44674] Re: Stephen's fantasy imperial Britain To: "U.S. Metric Association" <[email protected]> Date: Tuesday, 14 April, 2009, 1:50 AM Actually, the antifreeze will elevate the boiling point and depress the freezing point. At least in US cars, the coolant MUSTN'T be water, as the pressure cap alone is not sufficient to keep water from boiling. You need the coolant to at least approximate the recommended 50% antifreeze mixture. Overheat indication is around 135 °C, with 130 °C in the normal range. With a 104 kPa / 15 PSI pressure cap, water will boil about 124 °C and is not a satisfactory coolant. --- On Mon, 4/13/09, Ken Cooper <[email protected]> wrote: From: Ken Cooper <[email protected]> Subject: [USMA:44669] Re: Stephen's fantasy imperial Britain To: "U.S. Metric Association" <[email protected]> Date: Monday, April 13, 2009, 8:25 PM OK - Let's dissect Stephen's post. The LCD display showed my engine temp in Celsius - I have it that way as the coolant is water - thus? I think you can see my thinking here!! ;-) A beautiful example of Stephen's misdirection! I find it very hard to believe that his car has a coolant system that works with pure water at atmospheric pressure. The coolant mixture is highly unlikely to boil at 100 degrees C as he implies. The anti-freeze will lower the boiling temperature and the fact that the system is pressurised will act in the opposite direction. In addition, I've never owned a car that displays the coolant temperature in any other way than a uncalibrated gauge. Can Stephen confirm which car he has that displays coolant temp via a digital display & how it indicates that the coolant temp is too high?
