Redline WaterWetter(R) Review

Michael Posner
by Michael Posner

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.

Michael Posner
Michael Posner

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  • Jdimmers Jdimmers on May 02, 2014

    We are going to use waterwetter in 1 or 2 weeks in our stock-cars with 2.0 pinto engine with plain water in the cooling system and no thermostats. one of the cars has a small cooling problem due to a strong bend in one hose after fixing that we use two 12 inch vans to help in cooling. Will be nice to see engine temp stay at around 95 degrees Celsius without having to use the vans. Modern engines often use special coolants adding anything to that sort of coolant can cause problems, I think Nissan was mentioned with problems they normally use red coolant (at least they do over here in Europe) and VW/Audi use the pink stuff wouldn't ad it to those either. Our race cars are only allowed with plain water and an addition like this that doesn't cause the track to become slippery in case of an emergency

  • Ra60f Ra60f on Mar 22, 2016

    Interestingly what no one here seems to have pointed out is that, if this product does what it says it does, which is (simplistically) improve heat transfer between the engine and the coolant, then the effect of the product would not be measured by only the hot coolant temperature (i.e. As the coolant exits the engine) but by the difference between the radiator inlet and outlet. Theoretically, the coolant entering the engine would be colder than prior to using the product, and the difference between the before and after hot temperature wouldn't mean much. Redline probably uses that number because it's easier for dumbasses to understand and "believe" the product is doing something. In fact, I would even feel better if the radiator inlet temperature went up slightly, because it would mean the coolant was absorbing more heat from the engine components.

  • Canam23 I believe the Chinese are entirely capable of building good cars, BYD has shown that they are very forward thinking and their battery technology is very good, BUT, I won't buy one because I don't believe in close to slave labor conditions, their animosity to the west, the lack of safety conditions for their workers and also the tremendous amount of pollution their factories produce. It's not an equal playing field and when I buy a car I want it made with as little pollution as possible in decent working conditions and paying a livable wage. I find it curious that people are taking swipes at the UAW in this thread because you can clearly see what horrific labor conditions exist in China, no union to protect them. I also don't own an iphone, I prefer my phones made where there aren't nets around to catch possible suicide jumpers. I am currently living in France, Citroen makes their top model in China, but you see very few. BYD has yet to make an impression here and the French government has recently imposed huge tariffs on Chinese autos. Currently the ones I see the most are the new MG's, mostly electric cars that remind me of early Korean cars, but they are progressing. In fact, the French buy very little Chinese goods, they are very protective of their industries.
  • Jerry Haan I have these same lights, and the light output, color, and coverage is amazing!Be aware, these lights interfere with AM and FM radio reception with the stereoreceiver I have in my garage. When the lights are on, I all the AM stations havelots of static, and there are only a couple of FM stations that are clear. When Iturn the lights off, all the radio stations work fine. I have tried magnetic cores on the power cords of the lights, that did not makeany change. The next thing I am going to try is mounting an antenna in my atticto get them away from the lights. I contacted the company for support, they never responded.
  • Lou_BC Are Hot Wheels cars made in China?
  • DS No for 2 reasons. 1-Every new car pipelines data back to the manufacturer; I don't like it with domestic, Japanese and Euro companies and won't put up with it going to Chinese companies that are part financed by their government. 2-People have already mentioned Vinfast, but there's also the case of Hyundai. Their cars were absolutely miserable for years before they learned enough about the US market
  • Theflyersfan Well, if you're on a Samsung phone, (noticing all of the shipping boxes are half Vietnamese), you're using a Vietnam-built phone. Apple? Most of ours in the warehouse say China, but they are trying to spread out to other countries because putting all eggs in the Chinese basket right now is not wise. I'm asking Apple users here (the point of above) - if you're OK using an expensive iPhone, where is your Made in China line in the sand? Can't stress this enough - not being confrontational. I am curious, that's all. Is it because Apple is California-based that manufacturing location doesn't matter, vs a company in a Beijing skyscraper? We have all weekend to hopefully have a civil discussion about how much is too much when it comes to supporting companies being HQ-ed in adversarial countries. I, for one, can't pull the trigger on a Chinese car. All kinds of reasons - political, human rights, war mongering and land grabbing - my morality is ruling my decisions with them.
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