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What Kind of Fluid Goes in a Floor Jack?

Floor jacks operate on hydraulic fluid, and by choosing the right oil for your floor jack, you ensure the above-par performance of the jack. If you’re a beginner and planning on refilling your floor jack by yourself, the first question that fries up your brain is - what kind of oil goes in a floor jack?

Read this guide till the end, for here; we have spelled out all the necessary pointers for choosing the ideal floor jack oil type.

To learn what kind of oil to use for hydraulic jack, you’ve got to know what properties to look for in a floor jack oil. Here’s a list we’ve made for you.

Features of a Good Hydraulic Jack Oil

1. Viscosity

The jack oil should have a viscosity within the range of 22 to 32 centistokes (cSt) between temperatures of -40ºF and 450ºF.

Below this viscosity range, the oil has a lower lubricating capacity, causing leakage and damage to the parts. Above the range, the oil cannot be pumped through the system efficiently. 

2. Oxidation Stability

Antioxidant additives enable the fluid to resist the damage caused by heat during oxidation.

3. Thermal Stability

The oil must be able to operate across a wide temperature range and withstand high temperatures. Lack of thermal stability causes sediments and varnish to accumulate, clogging filters and thus lowering flow rates.

4. Rust and Corrosion Resistance

Corrosion and rust inhibitors in the jacking oil protect its metallic parts from damage due to reactions with water and chemicals.

5. Hydrolytic Stability

Oils without hydrolytic stability hydrolyze in water and clog valves and filters by forming precipitates of inorganic salts. Result? Failure of the system and reduced machine life.

6. Wear Resistance

The protective layer created by anti-wear additives in fluids prevents damage from frictional contact. This makes the machine perform better and last longer.

7. Filterability

Floor jack fluids need advanced filtration methods that filter out precipitates but don’t remove critical additives.

8. Cold Flow Additives

These allow the jack to function smoothly in freezing temperatures.

Recommended Hydraulic Fluid

A floor jack fluid operates to transfer power and control the system. So, besides the features mentioned above, the fluid must be non-compressible, non-volatile, and foam resistant.

The most recommended oils are ISO 150 and 8W32 jack oils, as they come with most of the aforementioned characteristics and the required additives.

It’s generally recommended that you use a monograde oil with a low viscosity grade. But hydraulic jacks that need to function in low temperatures require multigrade oil to keep viscosity within acceptable levels across a broad temperature range.

Recommended Hydraulic Fluid You Can Use in Jack

Our Top Picks for Hydraulic Jack's Oil:

Ideal Substitutes for Hydraulic Fluids- Yes’ and No’s

If you can’t find an oil specifically meant to function as a hydraulic fluid, there are substitutes. But the wrong fluid may not be compatible with the jack and cause damage. So, we’d recommend not to consider substitutes from the beginning.

Vegetable oils such as soy, canola seeds, and sunflower oil can be used as an alternative to hydraulic oils. Although expensive, these oils are nontoxic, biodegradable, and very lubricating. However, low oxidation stability and inability to function in the cold are some of their drawbacks.

Many beginners ask, “Can you use transmission fluid in a hydraulic jack” or “Can I use ATF instead of hydraulic fluid?”

Apparently, you can use ATF (Automatic transmission fluid) depending on the fluid’s viscosity and in small manually handled jacks. ATF isn’t the #1 substitute for a larger jack because additives in it can damage the jack’s seal, and it also foams in high pressure.

FAQs Users Also Ask

Can I use brake fluid in a hydraulic jack?

Ans: No, because brake fluids contain additives that impair the seals of a floor jack.

Can I use motor oil in my floor jack?

Ans: Motor oil doesn’t have the level of viscosity and temperature endurance needed for a hydraulic jack. So, you may rule this one out.

Can I use engine oil in a hydraulic jack?

Ans: Engine and hydraulic oils have similar additives present in them, so you can use only lightweight engine oil for your jack.

Can you use gear oil in a hydraulic jack?

Ans: No, because gear oil is more viscous than hydraulic oil, and these fluids are formulated to perform different jobs.

Final Words

Now that you know what kind of fluid goes in a floor jack, it’s time to budget your expenses, look through the available options, and select the one that meets both your jack’s and pocket’s demands.

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