From Referral by an Existing Customer to First Municipal Delivery in Yinchuan: How Chengli Secured the Order Through Reputation. In winter 2025, a municipal sanitation department in Yinchuan urgently required a batch of sewage treatment vehicles for temporary sewage pumping and emergency response following completion of urban pipeline renovation. Given that local winter temperatures frequently drop below -15°C, the buyer’s top concerns were cold-weather engine startability, low-temperature hydraulic system stability, and a dedicated winter maintenance plan. After one month of market research, they selected Chengli Special Purpose Vehicle Co., Ltd. and placed an initial order for four units of the CN6 Dongfeng 3308 mm wheelbase sewage treatment vehicle, with a budget of approximately RMB 222,000–277,000 per unit (based on publicly available tender information). This was not Chengli’s first appearance in Northwest China. As early as 2023, Chengli delivered five 5-cubic-meter water-sprinkling trucks to a sanitation station in Gansu Province; the customer reported that the chassis was robust and upper-structure after-sales service was highly responsive. This positive reputation, spread through industry word-of-mouth, prompted the Yinchuan procurement team to proactively contact Chengli’s sales manager, Ms. Zhang Yue (Tel: +86 ). 'We consulted three manufacturers during our evaluation; Chengli was the only one able to provide comprehensive low-temperature test data,' stated the Yinchuan procurement officer during a follow-up visit. Chengli’s CLW5070GSSD6 model (Announcement No.: CLW5070GSSD6) successfully completed a 72-hour cold-start test at -20°C; its hydraulic system used low-temperature-specific hydraulic oil to ensure smooth operation without jamming under severe cold conditions. Case Background: Three Key Winter Wastewater Treatment Challenges in Yinchuan. Located in Northwest China’s high-altitude, frigid region, Yinchuan faces unique challenges in winter wastewater treatment: Difficulty in Cold-Weather Engine Starting: Conventional diesel engines often fail to start reliably below -15°C, compromising emergency response efficiency. Risk of Hydraulic System Failure: At low temperatures, hydraulic oil viscosity increases significantly, reducing pump efficiency and potentially damaging seals. High Maintenance Costs: Absence of targeted winter maintenance protocols leads to frozen pipelines, stuck valves, and other failures. The buyer explicitly required vehicles capable of reliable starting at -25°C, continuous hydraulic system operation down to -20°C, and after-sales provision of specialized winter maintenance guidance. Leveraging its Suizhou production base (No. 1 Chengli Avenue, Suizhou Economic Development Zone, Hubei Province) and Dongfeng chassis nationwide warranty network, Chengli delivered a tailored solution. Solution Overview: How Chengli Meets Low-Temperature Operational Requirements. The vehicles delivered by Chengli are built upon the Dongfeng 3308 mm wheelbase chassis, equipped with a CN6-compliant engine, and feature the CLW5070GSSD6 official announcement design for the upper-structure. Key configurations include: Cold-Weather Starting System: Standard-fit intake preheating device and battery thermal insulation cover—verified to achieve engine start within 30 seconds at -25°C. Low-Temperature Hydraulic System: Uses L-HV32 low-temperature hydraulic oil, combined with an electrically heated hydraulic oil tank, maintaining oil temperature above 10°C even at -20°C. Insulated Piping Design: Critical pipelines wrapped with polyurethane insulation layers and fitted with electric heat-tracing cables to prevent freezing. Additionally, Chengli provided a detailed winter maintenance protocol, including daily post-operation drainage to prevent freezing, periodic replacement of low-temperature filter elements, and standardized hydraulic system preheating procedures.