Cooling Additives

Redline's Water Wetter has been on the market for years now, promising to knock up to 30 degrees off your car's running temperature by simply adding it in place of conventional glycol (antifreeze) coolant in your car's cooling system. It sounds gimmicky, but racers swear by the stuff, and Redline actually provides independent testing and scientific explanations on their site to "prove" Water Wetter's mettle. Naturally, it stood out as a great Fact or Fiction candidate.

As heat generated by an engine is transferred to coolant, localized boiling often occurs where coolant and metal meet. Since coolant absorbs heat far better in liquid form than as a gas, maximizing cooling efficiency means minimizing the amount of boiling coolant gas (vapor) that contacts the engine's metal. According to technical data available on Redline's website, Water Wetter reduces the surface tension of liquid coolant; in short, allowing smaller vapor bubbles to form when boiling, which can more easily move away from the metal's surface-meaning more liquid can contact the hot metal surface for better heat transfer.

The Test
Most cars' factory temperature gauges aren't known for their accuracy, so we called upon Auto Meter gauges to monitor this month's testing. With a 0-400 degree gauge monitoring coolant temperature at our '93 Miata subject car's radiator outlet, and a 0-250 degree gauge monitoring its cylinder head temperature at three specific points, we put the car through three different stages of testing, with the car's cooling system first filled either with the manufacturer-recommended 1:1 water/glycol (antifreeze) mix, or with the Redline-specified 32:1 water/Water Wetter mix.

Test 1
Idle Temperatures
From a cold start, the Miata was idled to operating temperature and monitored through three cycles of maximum and minimum temperature fluctuation, governed by its automatic electric radiator fans, and temperatures were recorded. Coolant temperature remained consistent, as it triggers the operation of the fans, but the Miata's cylinder head ran an average of 5 degrees cooler with the Water Wetter mixture than with the glycol mix.