Te lo quoto.
Concept: There are coolants better than typical antifreeze.
Theory:
Antifreeze will keep your engine coolant from freezing in the winter, and it raises the boiling point of water. It doesn't really do anything to improve heat transfer (remember, that's the idea of a cooling system). Evans Cooling offers NPG and NPG+ non-aqueous propylene glycol products. We used NPG+ which has a freezing point of -40 degrees (compared to -30 degrees for 50/50 water/ethylene glycol antifreeze mixture) and a boiling point of 375 degrees (255 for a 50/50 mix of water/antifreeze).
This higher boiling point means that there is liquid coolant around hot spots in the engine such as the exhaust valve areas in the heads. Water and 50/50 mixes of ethylene glycol-based coolants vaporize in these areas and lose their ability to transfer heat. The operating temperature will probably not decrease (in fact, it may increase slightly). The fact that there will be heat transferred from the hottest spots in the engine means the engine will escape damage up to 280 degrees. This coolant also has anticorrosion properties, and its lifetime is indefinite--you'll never need to change it.
What we did:
Completely drained the coolant and replaced it with Evans Cooling NPG+.
Cost: $22 per gallon, $66 for our application.
What happened:
The operating temperature didn't decrease, but the engine did run at a higher temperature without spitting coolant into the overflow. This seemed to confirm what Evans Cooling claims about its product. Our testing procedure included two idling tests and a casual drive at part throttle, but the sand dunes proved to be the toughest part. Horsepower is heat, and several blasts over and around the dunes built plenty for the cooling system to try to deal with. Every cooling problem is caused be inadequate airflow, water flow, or heat-transfer capability. We attempted to improve airflow at higher engine speed by replacing the electric fan with a Flex-a-lite metal flex fan and then a Flex-a-lite plastic fan. A fan shroud directs the airflow of a mechanical fan through the radiator instead of around it. We tested with and without a fan shroud to prove or disprove this theory--we may have only confirmed that we have bigger problems. Evans Cooling NPG+ is a radical idea in coolants. It concentrates on improving heat transfer in addition to raising the boiling point and lowering the freezing point. To ensure the system is free of water, you can hot purge the system by running the engine at about 275 degrees which will vaporize the water, pushing it out the overflow hose. We experienced no engine damage during this process.
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