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  • Cassie Farley

An Inside Expert’s Advice on Water Soluble Hydraulic Fluid; It matters more than you think!

The age-old question for Wash Owners, why should I convert from Hydraulic Oil to Water Based Hydraulic Fluid? This topic has been debated for years with many different opinions. Let’s dive deeper into the topic and address the pros, cons and misconceptions.

Day to day operations at a car wash can certainly be a handful even when all operations are running correctly, however things can take a terrible turn for the worse if a hydraulic line is blown. If you’ve run a wash with hydraulics, I’m sure you have experienced this in some form. Let’s look at a scenario in which a hydraulic line breaks from two perspectives. First a wash using Hydraulic oil. Then we will look at the same incident using water based hydraulic fluid.

It’s a typical sunny day, the wash is busy and all is well. Suddenly it happens. A hydraulic line blows and sprays black hydraulic oil everywhere. The mitters are dripping oil, the car passing through is sprayed. This hose is shooting oil all over the place. The wash attendant quickly jumps for the button and shuts down the wash. Now it's time to assess the damage. The wash will need to be temporarily closed. The mitters need a thorough hand scrubbing (anyone who has had to do this will tell you how grueling of a task this can be). The Hydraulic line is still broken and will need to be fixed. An assessment of the vehicle that was passing through will need to be conducted. Lastly, you’ll have to check out the pits to see if they were affected. If your running reclaim there’s a good chance your pits will need to be pumped. In summary the wash will need to be closed to have the hose replaced, mitters hand scrubbed, vehicle damage evaluated and possibly pits pumped out. This process would take quite some time and result in quite a bit of lost revenue on a busy day.

Now let’s examine this incident using Water Soluble Hydraulic fluid. The hydraulic line blows during a busy wash day, spraying water based hydraulic fluid everywhere. The attendant quickly shuts down the wash. Let’s assess the damage this time. The cloths and mitters have water-based dripping down them. They are rinsed with water and the hydraulic fluid quickly slides off. The car that was passing through has sustained no damage, simply will require to be rinsed and re-washed. The hose will still need to be replaced or fixed. The pits are not affected by the incident. Simply fix the damaged hydraulic line and your back online, drastically reducing the downtime and labor.

What we’ve learned thus far has always been a no-brainer to wash owners. Let's now address some facts, myths and misconceptions that cause many owners to hesitate:

Water Based Hydraulic Fluid Cost more Money!

This is True, however when considering the amount of lost revenue along with the frequency in which you will need to replace the fluid you will likely find it to be cheaper to stay water based. Also, a common overlooked fact is insurance companies can give you a discount for switching to a non-flammable and biodegradable product (this can vary state to state).

Water Based Hydraulic Fluid causes overheating!

False, reliable formulated hydraulic fluids like Aquablue have been proven to run 30 degrees cooler and can support temperatures up to 140 degrees Fahrenheit. If a powerpack is running over 140 degrees, it will at that point start breaking the formula of a fluid down. However, no powerpack should be running that hot, there is a separate issue causing heat in the pack to get that high.

Water Based requires a cooling fan to be installed!

False. Again, as mentioned above power packs should not be exceeding 140 degrees and the fluid is built to handle that.

Water Based causes your seals to go bad!

This is False. While it is true converting over from hydraulic oil to water based can cause seals to leak. This issue is not caused by the fluid, instead it's because of plaque buildup. Think of it like teeth if you have a cavity and its packed with plaque it may not bother you. However, when you go have a cleaning it clears all that plaque out and the underlying issue of a giant cavity is exposed. This is essentially what happens, seals have plaque buildup and the water based can flush that build up out causing the seals to show their true age.

Water Based Evaporates!

False. Powerpacks are generally a closed loop system therefore evaporation cannot escape. There are a few powerpacks with loose or removable lids where evaporation could possibly occur, in which case the viscosity would need to be examined closely to determine if its being affected.

Water Based needs to be replaced often!

False. Water based has three times the life of a standard hydraulic oil.

My powerpack will not be warrantied!

True & False. Every manufacturer can vary on this topic, most powerpacks however carry a one-year warranty. There is also no evidence to suggest water based causes any damage to power packs.

The converting over is difficult!

False. The process is quite easy, simply purge the system. Clean the powerpack, re add new fluid and replace the filter.

Different formulas over the years have caused many of these misconceptions to exist. We can speak only to Aquablue as to its performance specs and are happy to answer any questions you may have about your wash. Please feel free to visit our website at Call 800-977-8562 or email at

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