coolant question

[jakegday]

hello, i was wondering if a 50/50 mix of coolant and water would cool the engine better then a 70% coolant 30% water mix??

the reason im asking is i had a coolant leak, the water pump weep hole, well i changed the water pump, but before i replaced the water pump, it had gotten to the point where it was 100% water and the engine was running nice and cool, now that i have it fixed, and a near 50/50 mix, the engine runs a bit warmer then usual at the higher speeds, so thats why im wondering.......

before the leak ever began i did not have this issue with the warmer temps at higher speeds, i HAVE bled the system using the 1 "bleeder port" so i can only assume an air pocket is not the issue

[MagicRat]

Coolant has a lower heat capacity than water.
A gallon of water can absorb more heat (BTU's) for each degree of temperature increase than coolant can.
Therefore, the more coolant that is added to the mix, the less efficient it becomes at absorbing heat, despite the fact that coolant increases the boiling point of the mix.

All other things being equal, an all-water mix will cool better than a 50/50.

The 50/50 mix will cool better than a 70/30 mix.

Please note that cooler is not always better. Engines must attain a certain minimum temp in order to run efficiently, so if the engine is running 'warmer' but still in the normal range, it is not really a concern.