I. Introduction: Real Data Behind Three Years of Operation In early 2023, a municipal sanitation department in Langfang, Hebei Province, procured a batch of blue-plate sewage treatment vehicles for urban pipeline dredging and emergency sewage treatment. These vehicles feature the Dongfeng D6 chassis paired with Chengli’s proprietary superstructure, model CLW5070GSSD6 (technical specifications sourced from the MIIT official announcement). To date, these vehicles have operated continuously for over three years, accumulating approximately 80,000 km per unit. We collected complete maintenance records from five units to compile a detailed failure rate analysis report, aiming to provide objective reference data for similar government procurement projects. According to publicly available tender information, the budget for this batch was capped at approximately RMB 315,000 per unit; the final winning bid price was around RMB 260,000 per unit (based on local procurement conventions). As the supplier, Chengli Special Purpose Vehicle Co., Ltd. provided both the complete vehicles and subsequent service support. All analyses below are based on actual operational data. II. Failure Type Distribution: Which Issues Occur Most Frequently? Based on maintenance work orders for the five vehicles over three years, a total of 53 failures were recorded. Categorized by failure type, the breakdown is as follows: Failure Type — Occurrence Count — Percentage — Typical Manifestations Chassis-related — 18 — 34% — Clutch wear, brake pad replacement, tire punctures Sewage treatment system — 14 — 26% — Pump seal aging, pipeline blockages, filter screen replacements Electrical system — 10 — 19% — Sensor failures, control panel contact issues Hydraulic system — 6 — 11% — Hydraulic cylinder oil leakage, loose hydraulic pipe fittings Others (e.g., bodywork, interior components) — 5 — 10% — Wiper blade damage, door lock jamming Total — 53 — 100% Data shows chassis-related issues account for the highest proportion (34%), primarily reflecting normal wear under heavy-duty operation—e.g., clutch friction plates typically require replacement after ~30,000 km. Failures in the sewage treatment system (26%) concentrate on pumps and pipelines, directly correlated with operating duration and medium corrosivity. Electrical system failures (19%) mostly involve sensor malfunctions, all promptly resolved through Chengli’s lifetime superstructure service program. III. Chengli After-Sales Response Speed: How Long Does It Take from Reporting to Resolution? Of the 53 failures, 41 involved the superstructure (sewage treatment system, electrical system, hydraulic system). According to maintenance records, Chengli’s after-sales team’s average response times are as follows: • Call connection rate: 100% (24-hour hotline staffed at all times) • Remote guidance: For simple faults (e.g., clogged filters, sensor resets), resolution via phone or video guidance averages within 15 minutes • On-site repair: For faults requiring technician dispatch (e.g., pump seal replacement, hydraulic pipe replacement), average time from fault reporting to technician arrival is 4.2 hours (within Langfang region; Chengli maintains service centers across North China) • Repair completion time: Average resolution time for superstructure faults is within 72 hours (including parts logistics) Notably, chassis-related components (e.g., engine, transmission) are covered under Dongfeng’s nationwide warranty network. Local Dongfeng service stations in Langfang respond rapidly, averaging 2 hours for vehicle receipt at the workshop. Overall, Chengli’s after-sales response speed ranks favorably among peer suppliers.