What Hydraulic Oil for Excavator?

The hydraulic system is one of the key components of an excavator. And hydraulic oil, as the working medium of the hydraulic system, has a significant impact on the performance and lifespan of the entire machine. So, what kind of hydraulic oil should an hydraulic excavator choose?

What Hydraulic Oil for Excavator?

YUFAN, a leading professional excavator manufacturer in China, suggests that the hydraulic oil used in engineering hydraulic machinery should meet the following requirements:

(1) High static friction coefficient of anti-wear hydraulic oil

The hydraulic system requires the liquid to have a high static friction coefficient. However, the static friction coefficient of common anti-wear hydraulic oil is usually very low. It will cause the boom to move sluggishly and increase the risk of accidents.

(2) Excellent anti-wear performance

Construction machinery operates under high pressure, typically ranging from 21 to 35 MPa, sometimes reaching 42 MPa. In contrast, the pressure of industrial hydraulic systems is between 15 and 25 MPa. High pressure can cause hydraulic pumps to wear out quickly, leading to early damage.

Therefore, this type of anti-wear hydraulic oil must have superior anti-wear performance. YUFAN recommends using the following type.

✅ HM type (anti-wear hydraulic oil)

Base oil: refined mineral oil, anti-wear agents (such as zinc, ashless agents), anti-oxidation and rust-preventing agents

Features:
1️⃣Outstanding anti-wear performance, extending the lifespan of pumps and valves.
2️⃣Suitable for high-pressure hydraulic systems (such as excavators, injection molding machines, metallurgical equipment).
3️⃣Main domestic types, including zinc-containing (Zn) and ashless formulations (environmentally friendly).

Common grades: HM-32, HM-46, HM-68.

(3) High antioxidant performance

The hydraulic systems of crawler excavators all have a walking system, so the structure of the hydraulic system is compact, the oil tank is small, and there is no dedicated oil cooler. The working temperature is high, generally ranging from 80 to 100 degrees Celsius.

The high temperature accelerates the oxidation of the oil, shortening the oil change period. Therefore, it is required that the oil has better oxidation stability.

(4) Good filtration performance

Most excavators works outdoors on construction sites, exposed to wind, rain, sand, and dust. Water and solid particles easily enters into the hydraulic system. The hydraulic oil carrying particles will cause the precise piston pump to wear and lose power. Eventually damaging it. Thus this requires the oil to have good filtration performance.

YUFAN recommends select L-HM46# or L-HM68# hydraulic oil based on the applicable temperature.

(5) High-temperature hydraulic oil

This type of hydraulic oil is suitable for working environments with high temperature and high pressure. It can maintain stable lubrication performance at high temperatures and prevent oil film rupture. At the same time, high-temperature hydraulic oil also has good antioxidant properties, which can extend the service life of the hydraulic system.

(6) Low-temperature hydraulic oil

For excavators working in low-temperature environments, we can choose low-temperature hydraulic oil. Low-temperature hydraulic oil has lower viscosity and better fluidity, which can ensure the normal operation of the hydraulic system in low temperatures. For example:

✅ HV type (low-temperature hydraulic oil)

Base oil: deeply refined mineral oil or synthetic hydrocarbons, viscosity index improver

Features:
1️⃣ High viscosity index (VI > 130), good low-temperature fluidity (-30℃ and below can still be used).
2️⃣ Suitable for large temperature differences or outdoor equipment in cold regions.

Common grades: HV-22, HV-32, HV-46.

✅ HS type (ultra-low temperature hydraulic oil)

Base oil: synthetic oil (such as polyα-olefin PAO)

Features:
1️⃣ Extreme low-temperature performance (-40℃ and below), good high-temperature stability.
2️⃣ Used in harsh environments such as polar scientific expeditions, special military equipment, etc.

Selection Suggestions

1. Viscosity: Choose based on equipment requirements (e.g., HM-46 is suitable for most excavators).
2. Ambient Temperature: Select HV or HS for low temperatures, and HM or fire-resistant type for high temperatures.
3. Pressure Grade: High-pressure systems must use HM type.
4. Environmental Requirements: Select biodegradable oil for sensitive areas.

FAQ：

1. What hydraulic oil for Chinese mini excavator?

In foreign countries, it is advisable to select ISO VG46 anti-wear hydraulic oil for Chinese mini excavators and uniformly. This is the most reliable choice.

Just purchase the internationally renowned brands available locally: Shell, Mobil, Total.

For extremely cold regions, use 32 grade; for extremely hot regions, use 68 grade. Do not mix different brands.

2. What weight hydraulic oil for excavator?

Common 46 grade anti-wear hydraulic oil has a density of approximately 0.85 kg/L. 1 liter is approximately 0.85 kilograms.

The hydraulic oil tanks of small excavators (1–8 tons) are generally 40–100 liters, and when full, they contain about 34–85 kilograms.

The net weight of a large barrel (200L) of hydraulic oil is approximately 170 kilograms.