Introduction: Real-world Requirements from Initial Procurement to Iterative Upgrades. In the actual operations of a municipal sanitation department in a district of Foshan City, sludge removal is a high-frequency, high-load task. In 2022, the department procured five Dongfeng D6 blue license plate, 3-cubic-meter sludge tipper trucks (model reference: CLW5040ZWXD6) as its first batch, primarily for transporting sludge following urban pipeline cleaning and clearing rain-induced sediment accumulation. After one year of operation, due to the region’s hot, humid, and rainy climate—and especially the high operational frequency during the rainy season—the vehicles exhibited issues including blistering of anti-corrosion coatings, accelerated aging of sealing components, and hydraulic system leakage. By the end of 2023, the department launched its second procurement round, with a budget capped at approximately RMB 137,000 per unit, explicitly requiring enhanced durability and operational reliability under hot-humid conditions. Ultimately, the department again selected Chengli Special Purpose Vehicle Co., Ltd.’s upgraded Dongfeng D6 blue license plate, 3-cubic-meter sludge tipper truck, ordering five units—now performing well in active service. This article provides a detailed breakdown of this ‘requirement-driven iterative procurement’ case, tracing shortcomings of the initial batch to implementation of the upgraded solution, supported by real-world comparative data, offering practical reference for similar users. First-Batch Procurement Experience: Baseline Configuration and Early Performance. In 2022, to meet growing sludge removal demands, the municipal sanitation department of a district in Foshan City procured five Dongfeng D6 blue license plate, 3-cubic-meter sludge tipper trucks—their first such acquisition. The selection was based on the following key considerations: Chassis Requirement: Dongfeng D6 chassis, compliant with blue license plate regulations and suitable for narrow urban roads; operable with a Class C1 driver’s license. Capacity Requirement: 3-cubic-meter capacity, meeting daily small-batch, high-frequency sludge transport needs without overloading. Emission Standard: China VI compliance, satisfying local environmental regulations. Budget: Unit price approximately RMB 95,000–105,000 (based on publicly available tender information), sourced from an initial non-Chengli supplier. Following delivery, vehicle performance remained generally normal for the first three months. However, upon entering the rainy season (April–September), frequent rainfall in Foshan increased the average daily operating frequency of the sludge tippers from two to four or five cycles, exposing vehicles to prolonged high-temperature, high-humidity conditions. The operations team observed the following issues: Anti-corrosion coating failure: Rust spots appeared on the cargo box bottom and hydraulic oil tank surface within three months—especially severe at weld seams. Sealing component aging: Rear door rubber seals deformed under alternating hot-humid conditions, causing sludge leakage and road contamination. Hydraulic system leakage: Cylinder sealing rings aged prematurely due to heat and humidity, resulting in minor oil seepage. Increased failure rate under high load: Occasional lifting mechanism jamming occurred after continuous rainy-season operation. These issues directly raised maintenance costs and compromised operational efficiency. The department recognized that baseline configurations were inadequate for local hot-humid conditions and required a more professional, customized solution. Identifying Shortcomings and Upgrading Requirements. Drawing lessons from the first procurement, the department revised its procurement specifications by the end of 2023, focusing on the following core enhancements: Enhanced anti-corrosion coating: Full-vehicle application of two-component epoxy primer plus polyurethane topcoat; additional corrosion- and wea