Wheel loaders operating in high-latitude and alpine regions face severe low-temperature environments in winter, with temperatures often below -20°C and even below -40°C in extreme areas. Low temperature will cause a series of problems such as difficult engine start, poor fluid fluidity, seal embrittlement, battery capacity attenuation, and hydraulic system lag. If the maintenance is improper, it will not only be difficult to start the equipment but also cause serious failures such as engine cylinder wear, hydraulic pump damage, and pipeline cracking. This special maintenance guide aims at low-temperature cold regions, providing a complete set of low-temperature protection, daily maintenance, start-up operation, and emergency treatment measures to ensure the reliable operation of wheel loaders in severe cold environments.
Engine start-up difficulty is the most common problem in low-temperature environments. The main reasons include the decrease of battery capacity, the increase of engine oil viscosity, the poor atomization of fuel, and the low temperature of the cylinder. Before the arrival of winter, the engine must be maintained for low temperature. First, replace the low-temperature engine oil with low condensation point and good fluidity, which can reduce the starting resistance and ensure the lubrication effect at low temperature. The viscosity grade of the engine oil should be selected according to the local minimum temperature to avoid the use of ordinary engine oil in winter, which will lead to excessive starting resistance and even failure to start.
The battery performance decreases sharply at low temperature, and the discharge capacity is only about 50% of that at normal temperature. Before winter, test the battery capacity and starting current. If the battery is aging, replace it with a high cold-resistant battery. Clean the battery terminals, apply anti-freeze grease, and ensure good contact. Keep the battery fully charged at ordinary times. If the machine is parked for a long time, remove the battery and store it in a room temperature environment to avoid freezing damage. When starting, if the power is insufficient, use auxiliary starting power supply or preheat the battery.
Fuel selection is crucial in cold regions. Use negative No. 10, No. 20, or even lower-grade diesel oil according to the temperature to avoid wax precipitation and blockage of the oil circuit. Diesel wax precipitation will lead to poor oil supply, difficult start, and even flameout during operation. Install a fuel tank heating device and an oil pipe heating belt to prevent the diesel from waxing. Drain the water in the fuel water separator every day to avoid water icing blocking the oil circuit.
The cooling system should be replaced with antifreeze with sufficient low-temperature resistance. The freezing point of antifreeze should be 10-15°C lower than the local minimum temperature to prevent the cooling water from freezing and cracking the engine cylinder block and water tank. Clean the cooling system before replacement to remove scale and impurities. Check the thermostat, which should open and close normally to ensure that the engine can quickly reach the working temperature after starting.
The hydraulic system and transmission system also need low-temperature matching. Replace the low-temperature hydraulic oil and transmission oil with good fluidity at low temperature. High-viscosity oil at low temperature will lead to slow lifting, weak movement, high oil temperature, and accelerated wear of hydraulic pumps and gears. Check all hydraulic seals and oil pipes. Low temperature will make rubber seals brittle and easy to crack and leak. Replace aging seals and oil pipes before winter to avoid oil leakage during operation.
Lubrication system maintenance should also be adjusted for low temperature. Use low-temperature resistant grease to ensure that the hinge points, pin shafts, and rotating parts can be flexibly lubricated at low temperature. Grease that is too thick will solidify at low temperature, resulting in poor lubrication and increased wear. Lubricate each part in strict accordance with the cycle to ensure the normal operation of the working device and chassis.
The preheating system is an important guarantee for starting the loader in cold regions. Check the engine intake preheating device, glow plug, or intake air heater to ensure its normal operation. Before starting, turn on the preheating switch for preheating. After the preheating indicator is off, try to start again. Do not start the machine continuously for a long time, which will easily burn out the starter motor and battery. Each start time should not exceed 5 seconds, and the interval should be more than 1 minute.
After the engine is started, it is strictly forbidden to operate with load immediately. Let the engine idle at low speed to preheat, and wait until the water temperature and oil pressure rise to the normal range before carrying out the operation. During the idle preheating process, operate the boom, bucket, and other working devices several times to make the hydraulic oil circulate and improve the fluidity. Do not increase the throttle violently at low temperature, so as to avoid poor lubrication causing severe wear of engine parts.
The parking environment also affects the low-temperature performance of the loader. Try to park the loader in a heated garage or shed. If parked in the open air, cover the engine and key parts with thermal insulation materials. Drain the water in the air reservoir every day to avoid freezing and blocking the brake pipeline. Check the brake system before operation to ensure that the brake is flexible and effective.
In case of special circumstances such as oil circuit waxing and water icing, do not bake the engine, oil tank, and oil pipe with open fire, which is easy to cause fire. Use hot water or professional heating equipment for heating and thawing. After the fault is handled, check the fluid state again before starting.
In summary, the low-temperature maintenance of wheel loaders in cold regions focuses on fluid replacement, battery maintenance, preheating system inspection, and reasonable start-up operation. Strengthening winter maintenance and strictly following low-temperature operating procedures can effectively avoid failures and ensure that the loader can work normally and stably in severe cold environments.
