Inexpensive products that promise significant improvements to your car’s performance are almost always fool’s gold. This is especially true for engine additives (*cough* STP *cough*). However, there’s one company with a sterling reputation for delivering on its promises: Redline Synthetic. Since 1979, the Benicia, California company has been selling coolants, fuel additives and lubricants to the automotive, motorcycle, marine and industrial markets. As part of their range, Redline offer a product called WaterWetter®. They claim their potion can reduce car coolant temperatures by as much as 30ºF. That’s hot! I mean, not.

I reckoned it’d be a doddle to test the bottle. I’d simply run my car sans Redline’s additive and check the coolant temperature. Then, following the instructions on the bottle with my usual precision, I’d give my mount the magic potion, drive the same test loop and measure the temp again.

For the mechanically challenged, installation of WaterWetter® could not be easier. Assuming you can open your hood, open your hood (when it is cold, otherwise prepare for a scalding). Locate the radiator fluid intake point (RTFM if necessary). If you have too much fluid in the overflow tank (above the line labeled max), simply siphon off 12 ounces before installing, as overfilling is a really bad idea. Open the radiator cap (or on most modern cars, the overflow tank) and pour in the full bottle of WaterWetter®, funnel optional.

Before I reveal the results of my test, let’s look at Redline's claims for WaterWetter®'s effects on your cooling system:

• Doubles the wetting ability of water
• Improves heat transfer
• Reduces cylinder head temperatures
• May allow more spark advance for increased torque
• Reduces rust, corrosion and electrolysis of all metals
• Provides long term corrosion protection
• Cleans and lubricates water pump seals
• Prevents foaming
• Reduces cavitation corrosion
• Complexes with hard water to reduce scale

According to Redline, WaterWetter®’s greatest benefits accrue to those cars running straight water in their cooling system– which doesn't include anyone living in snow country. Translation: WaterWetter® offers all the normal protection benefits of regular coolant to people who don't use regular coolant. Oh, at a lower temperature. Well, theoretically…
Strangely, Redline’s own test results don’t square with their ad copy. Their technical literature only shows an eight degree Fahrenheit drop in a car with a 50/50 mix of water and coolant, and an eighteen degree Fahrenheit drop for a car running 100 percent water.

I used a VagCom system (reads sensor data directly from the ECU) for my tests. The pre-WaterWetter® installation delivered temperatures between 96 and 98 degrees centigrade (or 205 to 208 degrees Fahrenheit for the Americans). The post-installation temperature stayed steady at 96 degrees centigrade. Clearly, not the results advertised.

Other websites have tested WaterWetter® and also concluded that the overall decrease in coolant temperature is marginal. So WaterWetter®’s benefits either lie elsewhere (or nowhere). That assessment requires a certain level of trust with Redline products. In my experience, based on their oil products, they deserve this trust.

In reviewing the technical literature on Redline’s website, WaterWetter® claims to reduce hot spots in a car’s cylinder head. In theory at least, this reduces the possibility of localized overheating, improving engine longevity. Supposedly, WaterWetter® also protects aluminum products in the cooling system from excessive heat and cavitation caused by vapor bubbles forming inside the cylinder head and water pump.

In addition, for cars running straight water, WaterWetter® provides some additional protection. This includes traditional coolant roles of reducing corrosion and lubrication of water pump seals. For cars caned on the track or driven in the summer only, a water-only engine and cooling system solution will lead to problems. However, for cars with a tradition 50/50 mix of water and trad coolant, these benefits are already present without WaterWetter®.

WaterWetter® is available at auto parts stores and online for less than $10 a bottle. One bottle is good for an entire cooling system, and lasts as long as you properly keep fluid in your system (assuming you follow the recommended practice of flushing your cooling system every two years or 30,000 miles).

Since WaterWetter® has no readily measurable benefit, should you consider putting this in your car? That depends on your personality and your relationship with your car.

If you’re like me, you like buying stuff for your car in the HOPES of improving power, performance, mileage or longevity (I put Chevron Techron in my tank every 1000 miles). It’s true: I’m a sucker for products that have the POTENTIAL to improve the car, even without any possibility of measuring the results. This is doubly true if the cost isn’t prohibitive and there isn’t any risk of a downside.

In other words, fool’s gold is as good as gold to a fool.

From what I always undersm wtood is that you don't add this to your coolant, you put distilled water and this bottle instead of coolant. This prevents water from rusting the inside of your motor. Water is a better coolant than antifreeze. Problem is it will freeze in the winter. Maybe that's why it doesn't cool temps like the bottle says