In the past five years, the global construction machinery industry has undergone profound transformation driven by electrification, intelligence, digitalization and greenization. With China’s construction machinery accelerating its global expansion, Shandong Shitian Heavy Industry Co., Ltd. (hereinafter referred to as "Shitian Heavy Industry") has continuously upgraded its core technologies to keep pace with international standards, gaining wide recognition in overseas markets such as Europe and Russia. As winter approaches, low temperatures pose significant challenges to the stable operation and service life of small excavators, especially those exported to high-latitude regions. Combining the technological upgrading achievements of Shitian small excavators over the past five years, this article optimizes maintenance content inconsistent with current international technologies, provides a professional winter maintenance guide, and helps global users achieve scientific maintenance and efficient operation.

I. Winter Preheating Skills for Hydraulic Systems

In the past five years, the hydraulic system of small excavators has achieved iterative upgrades towards high efficiency, energy conservation and intelligence. Shitian small excavators have fully adopted the upgraded German Linde hydraulic system (synchronized with the latest international technical standards), which has better low-temperature adaptability and higher operational stability. However, when the hydraulic oil temperature is too low, the viscosity of the hydraulic oil increases and fluidity decreases. Hasty operation will still cause damage to hydraulic seals, blockage of pipelines, and even failure of hydraulic pumps. Therefore, full preheating is essential after startup in winter, and the operation should comply with the latest international safety operation specifications.

1. After starting the engine of Shitian small excavator, keep it running at medium speed (30%-50% of the maximum speed), and slowly operate the bucket to lift, lower and flip. Through repeated light-load operations, the hydraulic oil is gradually heated to complete the initial preheating. It is worth noting that for the intelligent hydraulic system upgraded in recent years, the preheating process can be assisted by the on-board intelligent monitoring system to realize real-time monitoring of hydraulic oil temperature and avoid blind operation;

2. During the preheating process, lift the machine body and rotate the left and right crawlers respectively to make the left and right travel motors bear uniform force and fully preheat, so as to avoid jamming of single-side motors due to low temperature. For models equipped with the latest anti-jamming technology, it is necessary to check whether the intelligent anti-jamming system is activated normally to ensure the smooth operation of the travel mechanism;

3. After the initial preheating, increase the engine speed to the maximum, keep the high-speed operation state, and let the bucket and arm continuously perform telescopic and flipping operations for 5 minutes to ensure that all components of the hydraulic system reach the normal working temperature (50-80℃). For models with energy-saving hydraulic technology upgraded in recent years, high-speed preheating operation can be combined with the energy-saving mode of the equipment to reduce fuel consumption while ensuring preheating effect, which is in line with the global trend of green and low-carbon development of construction machinery.

II. Winter Preheating and Inspection Points of Engines

The engine is the "heart" of small excavators. In the past five years, Shitian small excavators have fully upgraded their engine systems, adopting the latest international Tier 4 Final emission standards and hybrid energy-saving technology, which have significantly improved energy-saving and emission-reduction performance while ensuring power output. However, low temperature in winter is still likely to cause oil solidification, difficult startup, and increased engine wear if not fully preheated after startup. Therefore, the first step of getting on the vehicle is to do a good job in engine preheating and comprehensive inspection, and the operation process must comply with international technical specifications.

After getting on the vehicle, start the engine of Shitian small excavator and keep it running at low speed for 5 minutes. During this period, it is strictly prohibited to step on the accelerator sharply or run at high speed to let the engine gradually adapt to the low-temperature environment. At the same time, complete the following inspections item by item, combining the intelligent monitoring function of the upgraded engine:

1. Check the oil warning light to ensure it turns off normally; if it remains on, stop the machine to add oil or troubleshoot. For models with an intelligent oil level monitoring system, view real-time oil level data via the on-board display to improve inspection efficiency.

2. Inspect the machine body, engine base and pipeline connections for oil or water leaks. Winter low temperatures accelerate seal aging; replace Shitian’s upgraded high and low temperature-resistant seals promptly if leaks occur, and tighten connections to avoid affecting engine and hydraulic system operation.

3. Listen to the engine and check exhaust color: stable operation with no abnormal noise and light gray exhaust complies with international Tier 4 Final emission standards. Stop immediately to troubleshoot abnormal noise or black/white smoke to prevent further engine damage, in line with global environmental requirements.

4. Verify the charging indicator turns off normally; a persistent light indicates generator or battery faults. Shitian’s upgraded intelligent power management system automatically detects their status—repair promptly to avoid startup issues.

5. Conduct a comprehensive inspection of joysticks, crawlers, bucket teeth, etc., for looseness, jamming or damage. For models with an intelligent fault diagnosis system, check for fault prompts to ensure all parts function properly. 

III. Storage and Maintenance Measures for Equipment Idle in Winter

In the past five years, with the continuous improvement of international equipment maintenance standards, the requirements for the storage and maintenance of idle construction machinery in winter have become more stringent. For Shitian small excavators that are not in use for a long time in winter, proper storage and targeted maintenance must be carried out to avoid irreversible losses caused by low-temperature environment, ensure that they can be quickly put into use and exert the best performance when restarted. Combined with the technological characteristics of Shitian small excavators after upgrading, the specific measures are as follows, which are fully in line with the latest international equipment maintenance norms:

1. Before idling, clean the excavator surface thoroughly and check/fasten all fasteners. For intelligent detection models, use the on-board system to test fastener tightness for comprehensive inspection.

2. Check antifreeze, engine oil level and quality; replace turbid/black oil. Follow international low-temperature fuel standards to use -10# to -30# diesel (lower temperature requires more negative-grade diesel).

3. In extremely cold weather (below -15℃) with long-term shutdown (over 15 days), drain engine coolant and store the battery in a warm, dry place. Charge the battery regularly for intelligent battery management models, complying with international battery maintenance standards.

4. Start the engine every 7-10 days during idling. Preheat repeatedly in cold weather, idle for 5-10 minutes, operate cylinders and travel mechanisms without load, then run at maximum speed until the system temperature reaches 50-80℃ to ensure all parts work well.

5. Replace diesel (local temperature-adapted) and diesel filter; use local thickened engine oil and replace the oil filter. Repair hydraulic leaks promptly and insulate the fuel tank if possible, in line with international low-temperature maintenance specifications.

6. Inspect cooling system hoses for aging or damage and replace promptly. Add hot water to the water tank daily if possible (drain at night to prevent freezing). Antifreeze is not recommended in extremely cold regions, consistent with international maintenance experience.