I. Introduction: Three Years of Operations Data Reveal Real-World Performance In Zunyi, Guizhou—characterized by a humid, rainy climate—environmental conditions impose stringent demands on sanitation vehicles’ rust resistance, sealing integrity, and continuous operational reliability. In 2023, a municipal sanitation department procured a batch of Dongfeng Yizhan-series sewage treatment vehicles (model CLW5180GSSD6) manufactured by Hubei Chengli Special Purpose Vehicle Co., Ltd., for urban stormwater-sewage pipeline cleaning and emergency sewage treatment. As of 2026, these vehicles have operated stably for approximately three years. This article analyzes authentic maintenance records across three dimensions—failure type distribution, after-sales response speed, and spare parts supply assurance—to provide objective reference data for government procurement. II. Failure Type Distribution: Performance Tailored to Humid-Heat Conditions According to the department’s three-year maintenance log, a total of 27 repair incidents were recorded across 18 vehicles. The failure type distribution is as follows: Three-Year Failure Type Distribution of Dongfeng Yizhan-Series Sewage Treatment Vehicles (CLW5180GSSD6) in Zunyi Failure Type Occurrence Count Percentage Primary Cause Rust-protective coating peeling 8 29.6% Prolonged exposure to high humidity and corrosive sewage Sealing component aging/leakage 6 22.2% Accelerated rubber component fatigue due to hot-humid climate Hydraulic system oil leakage 5 18.5% Increased sealing pressure from frequent operation during rainy season Electrical system moisture-related failure 4 14.8% Water ingress into wiring connectors during heavy rain operations Pump impeller wear 2 7.4% Abrasive particles (e.g., sand and gravel) in sewage Others (e.g., pipeline blockages) 2 7.4% Improper operation or foreign debris blockage Data Source: Internal maintenance log of a municipal sanitation department in Zunyi (as of April 2026). Key Findings: Rust-protective coating degradation and sealing component failures constitute the primary vulnerabilities under humid-heat conditions—accounting for over 50% of all failures. This correlates directly with Zunyi’s annual average relative humidity exceeding 80% and high-frequency rainy-season operations (averaging over 200 days per year). Hydraulic and electrical system failures rank second but fall within the scope of preventable, routine maintenance. III. Chengli’s After-Sales Response Speed: Timeline from Repair Request to Resolution Per the department’s records, among the 27 repair incidents, Chengli’s after-sales team achieved the following average response times: • Time from phone-based repair request to engineer contact: ≤15 minutes (24/7 hotline: ) • Time from engineer dispatch to on-site arrival (Suizhou base is ~800 km from Zunyi): ≤12 hours (including remote diagnostics and urgent spare parts allocation) • On-site repair completion time: ≤6 hours (complex repairs—e.g., hydraulic system component replacement—completed within ≤24 hours) • Spare parts shipment-to-delivery time: Standard parts shipped within ≤24 hours; special-order parts delivered within ≤48 hours (leveraging nationwide spare parts central warehouses) The department head commented: “During one urgent nighttime incident in the rainy season, a vehicle experienced seal failure beside a main road. After calling 400, an engineer arrived on site within two hours—preventing sewage overflow.” Chengli’s commitment to “nationwide Dongfeng chassis warranty + lifetime upfit service” was fully validated in this case. IV. Spare Parts Supply Assurance: Zero Project Delays Due to Parts Shortages In government procurement, spare parts availability critically impacts vehicle uptime and operational readiness. In this case, none of the 27 repair incidents experienced delays caused by spare parts shortages.