HL, HLP and HVLP hydraulic oils - a complete comparison, differences and applications
Hydraulic oil is a key working component of any hydraulic system. The pump life, equipment stability, wear protection and the performance of the entire system depend on how correctly its category is selected. The most common classes are HL, HLP and HVLP. Despite the similarity of names, their characteristics and purposes differ significantly.
What does the HL/HLP/HVLP classification mean
These designations refer to the German standard DIN 51524, which divides hydraulic oils by the level of their operational properties - from basic to high-temperature. universal.
HL - basic hydraulic oil
Contains additives against corrosion and oxidation. Does not have anti-wear additives. Suitable for simple systems with low loads.
HLP - oil with anti-wear additives
Has an improved additive package: AW/EP, anti-corrosion, antioxidant. Used in most industrial equipment.
HVLP - highly stable oil for temperature extremes
Features an increased viscosity index (VI). Maintains viscosity both in frost and at high temperatures. The best option for street and mobile equipment.
Comparative table of oils HL/HLP/HVLP
| Characteristics | HL | HLP | HVLP |
|---|---|---|---|
| Standard type | DIN 51524-1 | DIN 51524-2 | DIN 51524-3 |
| Additives | Antioxidants, anti-corrosion | All HL additives + anti-wear AW/EP | All HLP additives + increased viscosity index |
| Protection against wear | Low | High | Maximum |
| Low temperature performance | Limited | Average | Excellent (up to -35°C) |
| High temperature performance | Average | Good | Excellent |
| Viscosity stability | Basic | Good | Very high |
| Suitable for street equipment | Most often not | Sometimes | Yes, ideally |
| Recommended areas of application | Simple hydraulic systems without load | 80% of machine tools, presses, industrial equipment | Excavators, loaders, special equipment, outdoor systems |
A detailed analysis of each type of oil
1. HL oil – basic level of protection
HL category oils are used in systems where there are no high loads and no risk of intensive wear of rubbing pairs. They provide a basic level of protection against corrosion, oxidation and oil aging.
- Affordable price
- Minimum set of additives
- Suitable for old equipment and simple pumps
- Not recommended for systems with pressures above 140-160 bar
2. HLP oil is a universal choice for most tasks
The HLP category contains anti-wear additives AW/EP, which significantly extends the life of the pump and hydraulic equipment. This is the most common type of oil in the industry.
- Suitable for most hydraulic stations and machines
- Withstands medium and high loads
- Stable at moderate temperature changes
- Ideal for equipment operating indoors
3. HVLP oil - for operation in conditions of temperature changes
HVLP oil is created for mobile equipment, outdoor hydraulics, winter operation and equipment with frequent starts/stops. Due to the increased viscosity index, it does not thicken in frost and does not thin out during heating.