Hello everyone. Today, let's discuss the proper usage of ashless anti-wear hydraulic oil. Many people select the correct oil but encounter issues during application-failing to change it when necessary, or indiscriminately mixing it when they shouldn't-ultimately leading to equipment damage. By following the guidelines below, you can largely avoid such errors.
Guideline 1: When should ashless oil be used?
Not all equipment requires ashless oil. Remember this fundamental principle: if a hydraulic system contains silver-plated components or copper alloy parts, you *must* use ashless oil. Examples include precision hydraulic systems featuring silver-plated valves, plunger pumps equipped with copper plungers, and servo valve systems.
If the system consists entirely of steel components, using zinc-containing oil is perfectly acceptable-and more economical. Avoid spending unnecessary money.
Guideline 2: Should the system be flushed before an oil change?
It depends on the situation.
Switching from zinc-containing oil to ashless oil: While the base oils of these two types are typically compatible, their additive systems differ. It is recommended that after draining the old oil, you flush the system once using the new oil (filling it to approximately 30%–50% of the system's capacity) before performing the final fill. Do not simply mix the two directly; doing so may compromise the anti-wear performance of the additives.
If the oil in the system has turned black or contains sludge: A thorough cleaning is mandatory. Use a specialized flushing oil or a low-viscosity ashless hydraulic oil to circulate through and flush the system; replace the filters, and then add the new oil.
Guideline 3: How much oil should be added? How do you check the oil level?
The ideal oil level should be maintained between 70% and 80% of the reservoir's total capacity. If the level is too low, the pump may draw in air, leading to foaming; if it is too high, the oil temperature may rise easily, accelerating oxidation.
After filling, start the equipment and allow the oil to circulate for a few minutes, then check the oil level again. Since oil will be retained within the pipelines and hydraulic cylinders, the fluid level in the reservoir will drop; you must top it up to the normal operating level.
Guideline 4: How often should the oil be changed?
There is no fixed answer; it depends entirely on the specific operating conditions. For Reference:
Normal Operating Conditions: Change every 2,000–4,000 hours or once a year.
High Temperature, Heavy Load, or High-Dust Environments: Change every 1,000–2,000 hours.
Precision Equipment: It is recommended to perform an oil sample analysis every six months; decide whether to change the oil based on the test results.
Key Indicators to Monitor: Focus on three metrics-if *any* of the following conditions are met, the oil should be changed: viscosity variation exceeds ±15%; moisture content exceeds 0.1%; or the Total Acid Number (TAN) has increased by more than 0.5 compared to the new oil.
Guideline 5: Refilling Requires Care
If the system develops a leak, it needs to be topped up. When refilling, keep the following in mind:
If you were originally using ashless oil, top up with ashless oil. Do not mix in zinc-containing oil; even adding just a small bucket will compromise the "ashless" properties of the entire oil reservoir, thereby reintroducing risks to silver-plated components.
Whenever possible, use the same brand and viscosity grade for the top-up. Additive formulations from different brands may be incompatible, potentially leading to the formation of precipitates or sludge.
Guideline 6: Storage Precautions
Ashless oil itself contains no zinc, but it is susceptible to contamination by water and dirt. Ensure container lids are tightly sealed and store the oil in a cool, dry place-never leave it exposed to the elements outdoors. Once opened, it is best to consume the oil within six months. For oil that has been stored for an extended period, inspect it for cloudiness or unusual odors before use.
In Summary
By selecting the right ashless oil and following the correct usage protocols, you can extend the service life of your hydraulic system by several years. The key takeaways are: verify your equipment's specific requirements; do not cut corners during oil changes; avoid indiscriminate mixing when topping up; and conduct regular oil analyses. Master these four points, and your system's reliability is essentially guaranteed.
