Thread: Disco 3 assembly

Originally Posted by shack

Adding ethylene glycol coolant at 50% rate increases boiling point to about 106° .

Then running a pressurized system at about 15psi will raise the boiling point another 25° .

Basically if you ran straight water with no radiator cap, you would boil at 100°, and lose pretty much all cooling ability, create hot spots and damage the engine.


But with coolant and pressurised system it'll maintain cooling ability up to about 130° , which funnily enough is beyond the safe operating temperature of an ICE!

Cheers
James

Raises boiling point and decreases cooling ability as it carries less heat than water.

"A 33% solution will provide about a 7 degree Fahrenheit (4 degree Celsius) increase in boiling temperature. A 50% solution (a.k.a. 50/50 solution) will raise the boiling point by about 15 degrees Fahrenheit (9 degree Celsius). That’s the good news. The bad news about ethylene glycol/water mixtures is that the solutions specific heat capacity is less than pure water. That same 50% mixture will have a specific heat capacity that is about 20-percent less than pure water. That means as a quart of the 50/50 passes through the cooling system it is only able to carry away 80 percent of the heat from the cylinders that pure water would be able to transfer. In a high-performance application, the desire is to maximize the waste heat transfer through the cooling system. As a result, pure water is generally teamed with a rust inhibitor additive and sometimes a cooling system booster that reduces the surface tension of the coolant. Some of the more popular boosters are available from Royal Purple (Purple Ice), RedLine (Water Wetter), and DEI (Radiator Relief)."

The information panel on the coolant container said that the difference between 50% & 30% solutions would be -37/129 to -21/124. So a 5deg C difference in boiling point seems relatively insignificant in Melbourne and -21deg Cis way cooler than I want to play in.
Further, I had 3.5litres of coolant on the shelf ready to use.

No doubt...

it doesn't change the fact though that irrespective of whether coolant is added or not, an engine is designed to run not far off of the boiling temp of water, making Pure water (ignoring the corrosion and freezing issues) an unusable product for cooling a motor.

If anyone is that averse to glycol, they could simply run Evans waterless, although that has similar issues to ethylene glycol coolant as regards heat removal.

Just got my roadworthy certificate - the tester said the car is in good condition. Now to get the registration and new number plates. Thanks to all on this site for the advice and help, including tooling loans, I'd still be struggling to understand this machine without this site.

Excellent Dave