All you should know about hydraulic fluids for automotive car lifts
Types of hydraulic fluid for automotive car lift It is quite difficult to say that a particular type of hydraulic fluid is the best because each of them has its pros and cons. So, you are the one that should consider some necessary factors before making a choice of hydraulic oil for your automotive car lift.
The main types of hydraulic fluid for car lift are R&O(quality and premium), AW32(quality and premium) and AW46(quality and premium). R&O protects hydraulic systems from rust and oxidation. That is why it is tagged R&O which means rust and oxidation. In addition, it contains anti-foam additives. It is a 10 weight oil with the additives.
While both AW32 and AW46 also protect hydraulic systems against rust and oxidation, they function better in protecting lifts against wear. So, AW stands for Anti-Wear. AW32 is approximately a 10 weight oil with the additives while AW46 is approximately a 15 weight oil with the additives. They are usually blended with refined naphthenic/paraffinic based oils. Both of them are also known as ISO32 and ISO46.
For R&O, AW32, and AW46, the major difference between their quality and their premium versions is that premium version has increased oxidation stabilizers. For instance, Quality AW32 is approximately a 1500-hour oil while Premium AW32 is approximately a 5000-hour oil and its increase in oxidation stabilizers accounts for the big difference.
By virtue of their anti-foam, anti-wear, and anti-rust properties, both AW32 and AW46 are the most recommended hydraulic fluid by car lift manufacturers. However, AW32 has a little edge over AW46. Being a10 weight oil, it performs better in all weather conditions.
How are hydraulic fluids rated?
To know the best choice of oil for your car lift, you also need to understand how hydraulic fluids are rated. They are rated by their level of viscosity. This property determines the ability of hydraulic oils to flow at different temperature. Lower numbers indicate thinner fluid and thinner fluids flow better.
Since AW32 is of a lower number than AW46, it flows better than AW46, especially in colder climate. This is why it is a more common choice. However, in a heated garage or during warm climate, AW46 is as good as AW32. Transmission fluid can also work as hydraulic oil for car lift but it is not recommended because it is too thin and can seep out of hydraulic cylinder seals. So whether you use 2-post lift, 4-post lift, low rise car lift, mid-rise car lift, or 4-post roller jack, AW32 is a good choice for you anytime.
When to change your hydraulic fluid
A lot of people change the oil in their hydraulic system after a certain number of hours. It is not a good idea to do so without analyzing the condition of the oil. This is often a total waste of money. It is like changing the oil in your car engine after three months even though you did not use the car for more than 10 times within those three months.
While number of hours is a good yardstick, you also need to analyze the condition of the oil. What matters most is the degradation of the oil as well as depletion of its additive package. A lot of factors collectively determine the rate of degradation of hydraulic oils. On the other hand, if your oil is degraded or its additives are depleted and you are still using the lift like that, you may reduce the life span of the lift and even void the warranty of its manufacturer.
In conclusion, the best way to know when to change your hydraulic fluid is through regular oil analysis. One major sign that indicates oil degradation is that your car lift can drop a little lower while in use. Once this happens, you should do a proper oil analysis and change your hydraulic fluid as quickly as possible.
