What color is hydraulic oil: a comprehensive analysis from normal status to abnormal changes
Hydraulic oil is an indispensable working medium in the hydraulic system. Its color can not only reflect the type of oil, but also visually reflect the health status of the oil. This article will combine the popular discussions on the entire Internet in the past 10 days to systematically analyze the meaning of hydraulic oil color, causes of changes, and countermeasures to help users quickly determine whether the hydraulic system is operating normally.
1. Common colors and corresponding types of hydraulic oil
| Color | Oil type | Main ingredients |
|---|---|---|
| Amber/light yellow | Mineral hydraulic oil | Base oil + antioxidant additives |
| Transparent and colorless | Synthetic ester hydraulic oil | Synthetic base oil |
| red | Aviation hydraulic oil | Phosphate group |
| green | Biodegradable hydraulic oil | vegetable oils |
2. Warning table for abnormal color changes
| unusual color | Possible reasons | Hazard level |
|---|---|---|
| milky white | Intrusion of moisture (condensation or seal failure) | ★★★ |
| dark brown/black | High temperature oxidation or pollution | ★★★★ |
| metallic luster | Metal particle contamination (pump/valve wear) | ★★★★★ |
| layered colors | Mixing different oils | ★★★ |
3. Sharing of recent hot cases
1.Hot discussions on construction machinery forum: The hydraulic oil of an excavator changed from amber to gray-black within a week. After inspection, it was found that the hydraulic filter element was broken, causing dust contamination. After the filter element was replaced, the system returned to normal.
2.Popular car maintenance videos: The gearbox hydraulic oil looked like a strawberry milkshake. It was diagnosed as a coolant leak that caused oil and water to mix. The repair cost was as high as 10,000 yuan, triggering discussions on regular oil inspections.
3.Industrial Safety Bulletin: A fire occurred due to carbonization of hydraulic oil in a factory. The accident analysis showed that the oil temperature exceeded 90℃ and was not dealt with in time. The related topic #hydraulic oil high temperature warning# became a hot search in the industry.
4. Color Maintenance Guide
| Maintenance measures | execution cycle | Expected results |
|---|---|---|
| Visual inspection of color | Before starting up every day | Detect early stage contamination promptly |
| Oil testing | every 500 working hours | Accurately grasp oil quality status |
| Replace filter | According to manufacturer's regulations | Keep oil lines clean |
| system flush | When changing oil | Remove residual contaminants |
5. Expert advice
1. Establish a hydraulic oil color file: Take photos and archive the new oil and the oil during each test to form a visual comparison database.
2. Use color comparison card tools: Hydraulic oil color comparison cards (such as the ISO 4406 standard) launched by many manufacturers can help quantify the degree of color change.
3. Intelligent monitoring trend: Use online monitoring equipment with color sensors to track changes in oil color in real time and generate trend charts.
By regularly observing the color changes of hydraulic oil and combining it with professional testing methods, potential faults in the hydraulic system can be discovered in advance and major losses can be avoided. When the oil color exceeds the normal range, it is recommended to conduct professional oil analysis immediately and take corresponding maintenance measures.
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