Evans Cooling NPG Waterless Coolant System

Published in the April 2010 Issue April 2010

Waterless coolant? Sounds contradictory, doesn't it? It's called Evans NPG+. It stands for Non-Aqueous Propylene Glycol. By taking the water out of the coolant, they've created a better, less hostile environment for your engine.

Engine cooling has become increasingly challenging as engine efficiency and technology have increased over the years. As higher horsepower and torque are produced, the temperatures are obviously more difficult to control. Automakers have increased radiator and fan sizes to keep up with the demand. However, they haven't provided a solution that addresses the core problem in cooling systems today-water.

Traditional coolant (ethylene glycol or propylene glycol) combines a 50/50 mix of antifreeze and water. The water in the mix conducts heat. The glycol is added to increase the boiling point and lower the freezing point of the water. The coolant also needs to inhibit corrosion in the cooling system because the water corrodes various electrochemically incompatible metals in today's engines.

When used in heavy-duty applications, like towing or racing with your diesel pickup, the water can fall short of the task at hand. In certain parts of the engine where high temps are generated, such as the cylinder head or upper portions of the engine block, metal temperatures can get hot enough to boil the water in the coolant mix. If the surface temperature gets hot enough, the boiling water forms a vapor barrier between the hot metal and the rest of the coolant. They call this "film blanketing," When film blanketing occurs, the metal temperature continues to increase, developing extreme hot spots in the engine.  

NPG+ has no water. It is inhibited 100 percent propylene glycol. By eliminating water from the cooling system, there are several benefits, including an increased boiling point to 375 degrees F without the need of pressurization. By raising the boiling point, you don't have the problem of boiling hot spots in the engine. Now the coolant is able to sweep the hot coolant away from the hot metal and transfer the heat more efficiently into the atmosphere through the radiator.

Now the coolant doesn't need to be pressurized to increase the boiling point, so you can use a low pressure cap on the radiator, which takes stress of off the hoses and radiator. The other benefit to eliminating water is: no water. You don't have to worry about water corroding the engine from the inside out.  

We decided to test NPG+ in our Project LBMC because it sees extremes temps, loads and power (1,318 rear wheel lb. ft. torque on the last dyno run). We flushed and purged all water and coolant from the cooling system and replaced it with Evans NPG+ coolant. The cooling system to date has functioned perfectly. NPG+ is also a "lifetime" coolant, so this is the last time we'll have to change our coolant.

The engine seems to run more efficiently in hot weather. When towing heavy loads up long hills in 90 to 100 degree F weather, we notice significantly less fluctuation in coolant temperature. We attribute this to the more efficient and consistent cooling attributes of the NPG+ coolant.

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