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What is the preferred Coolant to use these Days? Dexcool? Regular Prestone?

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Thanks, Engine and Additive Technology is evolving a lot these days. Just checking if a modern Coolant is preferred....


C

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I'm going to start switching over to Evans waterless coolant. Last forever and completely prevent corrosion

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What is the preferred Coolant to use these Days?
Dexcool? Regular Prestone?

My little Scamp Street/Strip is ready to roll. No heater Box.
318 w Magnum Heads, Aluminum Radiator.
It has a 180 Thermostat and I will use Water Wetter...


Thanks

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Water removes heat from a motor better than anti-freeze (propylene or ethylene glycol)

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Water removes heat from a motor better than anti-freeze (propylene or ethylene glycol)

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Snot true.

This misinformation is specifically addressed thoroughly in the book “Engine Cooling Systems” by Bohacz. Engine performance is lost due to water’s low boiling point. And engine damage is possible from unremoved heat.

Some may believe that water is the best coolant since it has a specific heat of 1. That would be true if an engine was only run at idle or low power output such as cruising. Water does an excellent job of cooling an engine until the load is increased, as in hard acceleration, and the water starts to boil in the cylinder head. When boiling in the cylinder head happens, the water stays cooler since there is less heat rejected into it, but the metal surface temperature of the cylinder head will be higher than it should be.

Your coolant temperature gauge may show normal or even cooler while your combustion chamber metal is overheating, because steam in the heads is a lousy coolant, and the higher heat around the combustion chamber metal never makes its way to the temperature sending unit or the radiator. A coolant with a low boiling point causes cooler temperature gauge readings because it is removing less heat from the engine. What you see on your dash gauge is the coolant temperature, but what you really need to worry about is the combustion chamber metal temperature.

An engine using water as a coolant and under constant load such as climbing a hill will have the coolant in the cylinder head be either in nucleate or crisis boiling states. Boiling water does not remove enough heat and requires detuning the spark advance and carb settings to make up for its low boiling point. Ethylene glycol/water and especially Evans have greater ability to transfer heat away from combustion chamber metal than water due in part to their higher boiling points and less tendency to form vapor bubbles. Evans, which boils at over 375 degrees, tends to stay in a liquid state under engine load and not form vapor filled bubbles next to combustion chamber metal that poorly conducts heat as does water when boiling.

Water with a specific heat of 1 boils at 257 degrees at 15 psi. 50-50 EG/water boils at 264 degrees at 15 psi. While it is true that Evans has a specific heat of about 0.7, the fact that it boils at over 100 degrees higher means it removes far more heat than either water or EG/water. Not only does it boil at over 100 degrees higher, it also has less surface friction allowing gas bubbles to release easier, recondense faster, and conduct more heat.

Advantages of Evans, a mix of mainly PG and some EG:

Contains no water and never causes corrosion or deposits.
Never needs changing (even though the color may darken over time).
Conducts more heat away from combustion chamber metal than anything else.
Allows a more aggressive engine build and tune-up.
Does not need the cooling system to be under pressure to raise the boiling point. In fact, due to almost no vapor pressure, a closed system won't pressure up.
Should never expand and boil over. You can remove the radiator cap at operating temperature with no result.
Very low surface tension works well in copper tube radiators and slightly decreases the load on the water pump.
Very low vapor pressure means very low loss from evaporation.

Evans which is a straight pour into the engine, contains no water, and is not mixed with water. I bought 4 gallons of Evans for under $160 on Amazon including freight, so it is pricey, but since you never have to change it, if you live long enough, some day it will be cheaper on paper than EG.

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