I. Project Background: From Referrals by Existing Customers to Recommendations by Peers In early winter 2025, a municipal sanitation department in Shenyang (hereinafter referred to as the 'Shenyang client') planned to procure a batch of 3308 yellow-plate sewage treatment vehicles for emergency cleaning and maintenance of urban sewage pipelines. Given that Shenyang’s winter temperatures frequently drop below -20°C, the client imposed stringent requirements on the vehicle’s cold-start performance, low-temperature hydraulic system stability, and winter maintenance solutions. Initially, the Shenyang client learned through internal channels that a district urban management bureau in a neighboring city had procured specialized vehicles from Chengli Special Purpose Automobile in winter 2024 and successfully operated them under severe cold conditions. A procurement manager from that bureau proactively recommended Chengli to the Shenyang client: 'We selected Chengli for its chassis options (Dongfeng or Sinotruk, both meeting China VI emission standards) and customized upper-structure design—especially its freeze-prevention preheating system, which ensures reliable engine start-up even at -25°C, and delivers exceptional hydraulic system stability.' Thereafter, the Shenyang client contacted Zhang Yue, Sales Manager at Chengli Special Purpose Automobile (Tel: +86 ), and requested detailed technical specifications for the 3308 yellow-plate sewage treatment vehicle. Zhang Yue promptly provided a customized solution based on official MIIT announcement parameters (e.g., technical extensions of models such as CLW5070GSSD6) and arranged an on-site inspection. Ultimately, after comparing multiple suppliers, the Shenyang client selected Chengli as its partner and completed delivery of the first batch of three vehicles in December 2025. II. Client’s Core Pain Points and Chengli’s Solution Analysis The Shenyang client explicitly outlined three core requirements in its tender documents: cold-start performance, low-temperature hydraulic stability, and a winter maintenance plan. Below is an analysis of how Chengli’s solution addresses each requirement: 1. Cold-Start Performance: Reliable Engine Start-Up at -25°C Shenyang’s extreme winter temperatures can reach -30°C, making standard diesel vehicles difficult to start. Chengli’s solution integrates an electrically heated fuel filter and glow plugs, complemented by the chassis’ built-in cold-start assistance system (e.g., Dongfeng chassis’ standard 'Cold-Start Assist Device'). Additionally, the upper-structure employs a circulating antifreeze-heated tank to prevent sewage from freezing inside the tank. Client feedback: 'During morning testing at -25°C, the vehicle started successfully on the first attempt—no failures occurred.' 2. Low-Temperature Hydraulic Stability: Specialized Hydraulic Oil and Thermal Insulation At low temperatures, hydraulic fluid tends to thicken, causing sluggish actuation or even system damage. To address Shenyang’s operating conditions, Chengli uses low-temperature hydraulic oil (with a pour point below -40°C) and wraps all hydraulic lines with rubber-plastic thermal insulation sleeves to minimize heat loss. During acceptance testing, the client specifically evaluated the hydraulic pump’s response time—achieving full operational readiness within just 3 minutes after startup, significantly outperforming the industry average of 5–8 minutes. 3. Winter Maintenance Plan: Lifetime Service Assurance Chengli’s service policy—'Original-chassis nationwide warranty plus lifetime upper-structure service'—earned strong trust among Shenyang clients. Sales Manager Zhang Yue (+86 ) thoroughly explained the winter maintenance checklist, including antifreeze concentration checks every 30 days, scheduled hydraulic oil replacement intervals, and tank anti-freezing measures. Furthermore, Chengli guarantees 24-hour direct shipment of spare parts, and its local Shenyang servi