The oils commonly used in front end loader mainly include engine oil, engine diesel, torque converter/transmission oil (hydraulic transmission oil), drive axle oil, hydraulic oil used in hydraulic system, and grease used in various hinge pins. The correct selection and use of these oils are of great significance to maintaining the normal operation of various systems, reducing wear and extending the service life of the machine.

1. Engine oil

(1) Viscosity grade and quality grade: The oil viscosity grade widely used internationally is the grade standard of SAE (Society of Automotive Engineers), such as SAE5W/40 or SAE15W/40. "W" means winter. The smaller the number in front of it, the thinner the viscosity of the oil, the better the fluidity, and the better the protection of the engine during cold start. The number after "W" is an indicator of the oil's resistance to high temperatures. The larger the number, the better the oil's protection performance at high temperatures. Higher viscosity oils also have relatively higher resistance to the moving system, which not only consumes power and increases fuel consumption, but also makes the oil easily oxidized, affecting protection during cold start.

API (American Petroleum Institute) grades are generally used to represent the classification of engine oil quality. It uses simple codes to describe the working capacity of engine oil. For diesel engines used in engineering machinery such as loaders, the oil quality grades range from "SA" to "SL". The later the letter, the higher the quality grade. With each increase in a letter, the oil's performance is better than the previous one, and the oil contains more additives to protect the engine.

my country's diesel engine oil viscosity grade and quality grade standard (GB11122-1997) equivalently adopts the above standards.

(2) Selection of diesel engine oil: For diesel engines used in caterpillar wheel loaders with harsh working conditions and heavy workloads, CD grade oil is recommended. CD grade SAE20W/40 is used in the south, and CD grade SAE5W/30 or 10W/30 is recommended for the north. Some imported engines require CE, CF and above engine oils, such as Cummins engines require CF-4 or above engine oils.

2. Engine diesel

Generally, diesel with a sulfur content of less than 0.5% is used. If the sulfur content is high, the oil change cycle will be shortened. Generally, loader diesel uses light diesel specified in GB252-1994, which is suitable for high-speed diesel engines with a full-load speed of more than 1000r/min.

3. Torque converter/transmission oil (hydraulic transmission oil)

(1) Functions of hydraulic transmission oil:

①Hydraulic transmission oil is the medium for energy transmission of the hydraulic torque converter.

②As lubricating oil for gears and bearings of the transmission.

③As hydraulic oil for the friction clutch of the transmission.

④As coolant for the torque converter and transmission.

(2) Selection of hydraulic transmission oil: The normal working temperature of hydraulic transmission oil is between 82 and 95°C, sometimes up to about 120°C. Due to the special requirements for hydraulic transmission oil, there is no national standard to specify its quality grade and viscosity requirements. The hydraulic transmission oil used in general loaders is the No. 6 hydraulic transmission oil in the enterprise standards of Lanzhou Refinery and Daqing Petrochemical General Plant in my country. No. 6 hydraulic transmission oil is mainly used for hydraulic transmission oil of internal combustion locomotives and engineering machinery.

4. Drive axle oil

(1) Gear oil: my country's vehicle gear oil quality classification standard GB7631.7~95 refers to the API quality grade classification and is divided into three types: CLC, CLD, and CLE. Among them, CLE is equivalent to GL~5 in the APL classification. It is recommended to use CLE grade gear oil for general loader drive axle.

(2) Drive axle brake oil (brake oil): The loader drive axle brake oil (non-full hydraulic brake) generally uses the HZY3 synthetic brake fluid specified in GB1298191, which is equivalent to the SAEL703C oil specified in API.

5. Hydraulic oil

Viscosity is an important performance indicator of hydraulic oil, because the lower the viscosity, the smaller the power loss and the higher the mechanical efficiency; and the lower the viscosity, the lower the volumetric efficiency, so the optimal viscosity meets the requirements of minimum wear of bearings and hydraulic pumps, and low-temperature performance must also be considered. Domestic hydraulic oil generally selects mineral oil type and synthetic hydrocarbon type hydraulic oil specified in GB11118.1 94. Due to the harsh working conditions of loaders, heavy workloads, and high hydraulic oil temperatures, advanced anti-wear hydraulic oil L HM32 and L HM46 models are generally used. Low-condensation hydraulic oil L HV32 and L HV46 models are recommended under low-temperature conditions.

6. Grease

A multi-purpose grease used abroad contains 1%-5% molybdenum disulfide, and it is also a suitable anti-corrosion agent. This grease is suitable for various hinge pins, spherical bearings, swing frame bearings, transmission shafts, etc., and has a wide range of uses. This grease must be a mixture of high-grade lithium-based and E.P. additives. It has the characteristics of stable chemical properties, no hardening, no leakage or dripping in the entire working range. Generally, grease No. 1 or No. 2 specified by NLGI (National Lubricating Grease Institute) is used. Its applicable temperature range is very wide and suitable for very low temperature occasions.

In the past, domestic loaders often used No. 3 or No. 4 calcium-based grease. Now this grease can no longer meet the requirements of loaders working under various climatic conditions (high or low temperature, humid and watery, etc.). Because lithium-based grease has many excellent properties, its oil change cycle is about 2 times longer than calcium-based grease, so lithium-based grease is now often used in loaders.