Boiling point of anti freeze

Good to know. Especially when I'm watching my coolant temp underway.
Thanks.

Yep, the pressurization is absolutely critical.

At 10,000 feet that temperature drops to about 237 degrees f.

Very good observation. Now for the fun part. Radiator caps as they age, tend to loose their ability to hold pressure in a cooling system. Caps should be replaced every couple years. Most people never do however. Mine goes in the trash every 2 years. That is especially important with a diesel motor as loss of pressurization of coolant can result in hot spots on the cylinder liners and big mechanical repairs.

All for a 6 buck part.

Good to know - I think I’ll get a new cap tomorrow. I’ve never changed mine, 10 yo truck!

A lot of newer cars have higher pressure systems, 18-20 psi.

RCMAN46 wrote:
At 10,000 feet that temperature drops to about 237 degrees f.

Do tell????

And there is nothing better than an original equipment brand radiator cap (and thermostat). My Kubota has 80% DOW anti-freeze plus Nalco cooling system treatment. The remaining 20% is distilled water hauled down from the states.

Better than 50/50 is 60/40 antifreeze/H2O, higher boiling point and lower freezing point.

joshuajim wrote:
I flushed and refilled my trucks radiator today. I noted on the bottle that a 50/50 solution of antifreeze/water will result in a 256 degree boiling point. This piqued my curiosity so I did a little research. In reality 50/50 antifreeze only raises the boiling point by 8 degrees. The 15# cap on the radiator is what gets you to 256.

:) Hi, this is how it works:

Water boils at 212 degrees.

A 15lb. pressure cap increases this to 3 degrees per pound. = 45 degrees.

Now you are up to 257 degrees.

With all of the above and a 50/50 mixture of coolant, you can add another 30 degrees. This gives you a grand total of 287 degrees before puking into the street.

This information was from a General Motors school while explaining that GM's idiot light comes on at 261 degrees. And if this vehicle only has water and a 15 lb. cap, (no coolant) it can boil over and the idiot light will never come on.