Oil is leaking from the tank mouth. If the welding seam of the tank mouth is leaking, the most direct reason is that the manufacturing process of the tank truck is not good, because the uneven welding seam causes stress. Unevenness, small cracks caused by long-term use of the tank truck, coupled with lax factory inspection, will cause such problems. Solution: Apply soap or alkali and scrape the cracks to control oil leakage within a certain period of time. Remember to be careful when scraping to avoid generating too much static electricity.